Zimmer Biomet Holdings, Inc.

Good morning, ladies and gentlemen, and welcome to the Zimmer Biomet second quarter 2020 earnings conference call. If anyone needs assistance at any time during the conference, please press the star followed by the zero. As a reminder, this conference is being recorded today, August 4th, 2020. Following today's presentation, there will be a question and answer session. At this time, all participants are in a listen-only mode. If you have a question, please press the star followed by the one on your push-button phone. I would now like to turn the conference over to Carrie Maddox, Senior Vice President, Investor Relations, and Chief Communications Officer. Please go ahead.

Thank you, Operator, and good morning, everyone. I hope you are all well and safe. Welcome to Zimmer Biomass Second Quarter 2020 Earnings Conference Call. Joining me virtually today are Brian Hanson, our President and CEO, and CFO Suki Ipagyai. Before we get started, I'd like to remind you that our comments during this call will include forward-looking statements. Actual results may differ materially from those indicated by the forward-looking statements due to a variety of risks and uncertainties. Please note we assume no obligation to update these forward-looking statements, even if actual results or future expectations change materially. Please refer to our SEC filings for a detailed discussion of these risks and uncertainties, in addition to the inherent limitations of such forward-looking statements. Additionally, the discussions on this call will include certain non-GAAP financial measures. Reconciliation of these measures to the most directly comparable GAAP financial measures is included within the earnings release found on our website at ZimmerBioNet.com. With that, I'll now turn the call over to Brian. Brian?

Great. Thanks, Carrie. And before we get started, I just want to say that I certainly hope that you're safe, your families are healthy, and and that you're doing everything you can to manage through this very unusual situation that we find ourselves in. Speaking of that, once again, we find ourselves in an earnings call where we're in different places. We're not all together. And my guess is we may have some mishaps, potentially anyway, when we hand off to each other. So I'm just going to apologize ahead of time for any mishaps that we see through the handoffs here and potentially any background noise we might get. You know, obviously this is an unprecedented time for all of us, a very challenging time. as we deal with the pandemic here in the U.S. and around the globe. And we, as a result of that, want to talk about the virus today. We want to talk about how we're managing through it. We want to talk about how we're modeling its potential impact. But we really also want to make sure that we spend some time on our underlying strength of the business that we have and our plans for long-term growth. And along those lines, I'm really going to try to center the conversation around three main topics. The first one is obviously our execution and the financial results in Q2, but really spend time in Q2 on the strength of the underlying business and why we're feeling confident in the things that we can control. The second thing would be around our broader modeling and our assumptions on a go-forward basis associated with the pandemic. It may not be as satiating as you want there, but we're certainly going to give you the best that we can on how we're looking at it. And then the final piece will be just on our long-term plan for growth. What are the things we're going to be focusing on to be able to get sustained growth in the future? So first, let's talk about the second quarter. And I want to begin with saying that safety, as I said last quarter, continues to be our top priority. You know, safety of our team members, our customers, our patients, the communities that we serve. And we continue to execute on that comprehensive global pandemic plan that we did develop last year, believe it or not, as I said before. We actually developed that plan before this all happened. And we've been putting that into action at the, you know, at the very earliest stages of COVID-19. And as a result of that plan and our additional safety protocols, we've definitely seen changes to how we work and have learned a lot about how we can more efficiently collaborate across the globe. You know, significant changes associated with that. But importantly, you know, these safety-related protocols have not caused disruptions in our supply chain, in our ability to meet our customer demand, and in our ability to serve those patients who rely on our technology and our products to improve the quality of their life. And I'd say I'm really proud of how seriously the entire ZB team has taken our collective safety. And I want to thank each and every one of our team members, especially our manufacturing and I just can't thank you enough. So in terms of our Q2 execution and performance, I'm going to cover some broad takeaways, and then I really want Sookie, after I finish, to get into more specific detail, maybe more than what we would typically get into, just given the current circumstances. So first, the recovery that we've seen to date and really specifically in Q2 is encouraging. Now, it's early, but so far it's been better than we expected. Based on what we are seeing and really just experiencing in the recovery, There's real reason for optimism. But given the number of unknowns related to COVID, you know, I would say it's more prudent to be cautiously optimistic right now. You're going to hear that theme throughout the discussion today. You know, we're watching closely and continuing to see rising patient demand, which is key, right? We've got to see that patient demand. And that's resulting, obviously, in increased procedure volumes. And very importantly, we're also seeing that the majority of surgeons and hospitals are ramping up capacity to support that demand. It's a pretty big variable associated with whether or not you can get that backlog patient and the new patient coming in. And so as a result of this, you know, our Q2 performance was better than we expected across all of our regions. And in particular, we saw strength in the U.S. And I've got to say, the U.S. recovery performance is really encouraging to me. You know, this is momentum that we're seeing despite the resurgence of the virus in many of our states. Importantly, this trend is continuing into July. even in some of the states with the rising COVID numbers like Florida, Texas, and Arizona. So, again, even though we're seeing the resurgence of the virus, we still are pretty bullish on what we're seeing in the U.S. so far. Clearly, and for good reason, everyone is going to focus on the impact of COVID in the quarter, and probably more importantly, its forward-looking impact on our business. And we're absolutely going to talk about that in a minute. But the last thing I want to discuss for Q2 centers more around the things we can actually directly control. even during the pandemic, and the activities that ultimately will drive durable growth and strengthen our business. So through the pandemic, I can tell you that we have remained maniacally focused on executing against our growth drivers. And that focus is delivering results. And we saw those in the second quarter. So I'm going to just start with what I know everyone wants to hear about is our progress with ROSA. Now, obviously, robotics plays an important part of our strategy on a go-forward basis. And importantly, we continue to see very strong demand for ROSA even through the pandemic. And also importantly, we're getting very good feedback from surgeons that are using the system. And while I can tell you that I'm not going to provide the level of detail I'm about to give you probably ever again, I do want to give you some additional insights into where we are with ROSA and the launch, just given the fact that it's being hidden right now with all the the clouds, I guess, associated with the COVID impact on our business. So as I'm just going to say, so we're now about a year away from the full launch of our business, about a year into that launch. And we now have about 150 rows and knee systems out in the globe. And the good news is we're seeing, with those units, very strong utilization per unit. Now, some of those are newly placed, so you're not seeing the same volume yet. But when a system's been out there for a while, we're getting very good utilization per unit. And if I just kind of add it up and I look at the current procedural volumes that we're seeing, we're really on pace to be doing about 3,000-plus cases per quarter. And just to put that into context relative to growth, that's more than double the procedural volumes that we would have seen in the fourth quarter of 2019. And by the way, that's inside of, you know, the pressure on elective procedures that we're seeing as a result of the pandemic. In addition to that, we've got a number of accounts in our active pipelines. active pipeline. Some of those will fall out, but based on the volume of accounts in that pipeline, we'll be very disappointed if we don't have between 200 and 300 ROSA systems out in the market by the end of this year. So I would just say for ROSA, we continue to see very strong momentum and remain on track, actually slightly ahead of our expectations for both system placements and procedures, even with the pressure of COVID in this environment. So good news, obviously, on the ROSA front. Another great example of strong innovation and commercial prowess is the persona revision story that we're seeing play out and saw play out in the second quarter. You know, our launch of the revision system is well ahead of plan, believe it or not, in receiving very positive remarks from current persona users, which is important. But even more importantly, we're seeing very positive remarks from competitive surgeons, which is where we want to make sure that we're focusing. And some of the key areas of feedback are really a lot of excitement around the ease of use of the systems. significant excitement around precision and the intuitive nature of the instruments that we have, which is important in this procedure, and also the ability to provide all the benefits of a more personalized fit for the patient that persona brings to the table and do this in a revision system, which again is unique in the marketplace. So just for perspective, the persona revision surpassed our expectations in Q2 and delivered the most successful quarter to date since launch. Let's kind of repeat that. It's the most Successful quarter dates since launch in Q2, which is the quarter that's been most impacted by the pandemic. The demand is still very robust even outside of that. We already have doubled the instrument sets originally anticipated for the launch to support that demand. And again, for context, this product is on a trajectory to reach close to $100 million in revenue during 2020. Now, some of that's going to be cannibalized, obviously, cannibalized revenue. And I would expect the cannibalization rate to be about 60%, 6-0%. So, again, on track to do $100 million or very close to it in 2020. And I would expect about 60% cannibalization of that revenue. And we also have continued our focus on driving our dedicated commercial team for extremities, as I've talked about quite a bit. And we've been very pleased that our Signature One Planner shoulder system continues to gain traction, again, even in Q2. Now, surge in registrations, just to give you some perspective, for Signature 1 increased nearly 60% in Q2, sequentially over Q1. And our recent FDA clearance also enables even greater integration of that system with our family of implants and guides. And so that's going to open up even more opportunities. We've also increased the portability of the system. We're really trying to make it more open architecture so that you can use it on your computer, but you can also put it on an iPad or an iPhone, so that if you're walking in and out of the surgery out of the operating room, you can still use the system, create that portability which surgeons wanted. So we're excited, again, about our shoulder franchise and the impact that the system will have on our success there. And then finally, my mobility. You know, our partnership with Apple continues to be a prime example of how research and development, investment, and tech innovation are going to drive the next wave of telemedicine advances. and we truly believe will change the patient and surgeon experience in our space. And with MyMobility, what we're really focusing on is ensuring that we have that patient-physician communication link that's even better than it was before, but allowing this to happen more virtually. The system also helps improve adherence to the pre- and post-patient requirements because that information is pushed to the patient when they need to actually do something. And very importantly, it's advancing the collection of and the analysis of patient-specific data points that ultimately can help the care team make the best and most personalized care decisions for that patient. In June, we announced with Apple a new application. It's going to be able to provide now gait quality functionality. within MyMobility, and that will happen this fall. And that's a pretty exciting development and a big step forward, no pun intended, in this remote data collection journey. Again, with the idea of collecting data that is personalized to the patient and ultimately, as a result of having that, provide better care decisions. So the MyMobility functionality in today's COVID environment is especially interesting because it does allow for this significant demand that we're seeing right now for allowing effective and engaged remote and virtual patient care. So we're excited clearly about my mobility. We were before the pandemic, but certainly this is giving us some additional steam in the marketplace. So moving to the second key area of focus for the earnings call, I want to talk about COVID-19 and our modeling assumptions for the rest of this year. And we're encouraged by what we saw in Q2 and are confident in our ability to continue to execute But we understand, and I think probably everybody does, the near-term uncertainty that COVID-19 brings. Our thinking regarding COVID is obviously changing. It's evolving. It's sharpening as we experience more of its actual impact on our procedures. And over time, we're also seeing the impact on various markets and submarkets. And so I like to think about just based on that knowledge that we're getting, we can refine our thinking here and explain it. really by talking about three major variables that I think we've got to pay attention to. One of those variables would be a tailwind for us created by the pandemic, and then two would be headwinds that we've got to pay attention to. So the first we talk about the tailwind would just be the backlog of deferred patients that we have built. You know, these are both the initial deferred procedures that we saw in the beginning and the building backlog that's continuing to happen. From a headroom standpoint, I really look at it two ways. One would be around those patient-specific factors, patient fear or unemployment, for instance. And then the second one would be around the recurrence of the virus. And I would think about that in two ways, the recurrence having an impact on actual bed capacity and the recurrence having an impact on policy decisions that could directly impact electric procedures. Okay, so that's kind of the variables that I think about in determining where we think this is going to go. Relative to the backlog, I think it's really important to note that the approximate value of this backlog, just for ZB, just for this company, is already worth about $700 to $800 million in revenue. That's the approximate value of the backlog already created. It's worth about $700 to $800 million in revenue, future revenue. And this value continues to grow. I mean, the fact is it continues to grow and will continue to grow until the market returns to normal market growth rates. Okay, relative to the headwinds, you know, given that we are currently seeing play out, I would say that patient fear and virus recurrence impacting specifically bed capacity are the two most significant threats, while I would say that policy decisions and unemployment concerns will be less material, at least based on the way that we're seeing policy decisions roll out right now. So the key takeaway, and I was giving a lot of information on these variables that I'm paying attention to, If the variables that I really just described continue to play out as they are today, we would expect that sequential improvement seen in Q2 would continue through the back half of 2020, but likely at a more modest pace in Q3 and Q4. Okay? So, just to repeat that, you know, if the variables that I just described continue to play out just as they are today, just what we're seeing today, we would absolutely expect the sequential improvement that we saw in Q2 to continue, In the back half, but it would be at a more modest pace. And another important aspect of this equation, and I think sometimes this is law, so it's an important thing to bring up, you know, is that the two most significant headwinds become non-variables once a vaccine is available. And the vast majority of those patients that didn't get treatment for either of these reasons become a tailwind eventually for our business, remembering that this is a progressive disease. And as a result of the progressive nature of that disease, the vast majority of these deferred patients will eventually reenter the procedural funnel and become a tailwind for us. Finally, I'd like to also spend a portion of my time today talking about the third category, which is our long-term plan for growth. And I can tell you that our strategy is relatively simple. You've heard me talk about it before. Not all of our businesses are going to be treated the same. All of our businesses are important to us, but they're not all going to be invested in or managed the same. Now, we have prioritized the high growth and most strategically relevant areas of our business, and we're going to make very disciplined investments there to continue to drive innovation, innovation centered around improving patient outcomes and also providing for procedure efficiencies. And to drive our strategic pillar of top-quartile performance in TSR, we have to focus most intensely on driving long-term growth in these key areas. Number one, and I've said this before, but number one, we must achieve above market growth in NEIS. And just given the size and scale of this business for us, we need to be ahead of market here. And we're going to do that by focusing more aggressively in the fastest growth sub-markets of NEIS, robotics, data and informatics, revision, like I just talked about. Next, we need to see and drive consistent at-market, actually at the higher end, of the market range for SET. We need to see that happen for our business. And we're going to do that, again, by focusing more of our attention in those most attractive sub-elements of SET. Also, we need to consistently deliver at-market performance and hits in the short term. That's all I'm asking for is at-market performance in the short term, but transitioning to above-market growth with our future robotics launch in this space. And then finally, while our other businesses, at least at this point, will not receive the same level of investment, and they will be managed differently, we still would expect that these businesses would drive in line maybe to the lower end of market growth for these areas. Okay, so that's the way we think about our businesses and the way that we're going to invest in them. And by focusing on these markets, just as I've described, we believe that over time our pursuit of consistent and sustainable mid-single-digit organic growth rates is absolutely possible. Now, to fuel the investment needed to drive this long-term growth and at the same time drive margin expansion over time, we've continued to focus and execute on our restructuring program. And the last piece when it comes to long-term growth is our M&A strategy, and this is going to be key for us. And it remains consistent with what we outlined in 2019 and earlier this year. We will continue to focus on high-growth areas and areas where we truly believe we have a right to win. And size is going to be a factor here as well, with a preference, at least at the outset, toward tuck-in deals. that we can easily integrate and operationalize while also maintaining an investment grade rating. So overall, I think it's obvious we feel confident in our business strength and execution, in the current pace of recovery from COVID, and in our long-term growth prospects. We've already learned so much from COVID-19. You know, while it's a challenge that none of us would really want to face, the fact is, you know, we do believe that it has reinforced the strength of our business strategy, and I believe that it's positively impacted our team engagement and our one ZV culture. And trust me, we will focus on leveraging our learnings to accelerate ZV's transformation. Now, at the end of the day, there's a lot of short-term variables associated with COVID that demand a level of caution. But make no mistake, we are very optimistic about our path forward. And with that, I'll turn the call over to Suki to get into more financial details. Thank you, Brian, and good morning, everyone. I hope all of you are well. I'd like to reiterate Brian's most recent comments that our underlying fundamentals remain strong and our long-term growth profile is compelling. Before jumping into the specifics, I would summarize our second quarter performance as simply being better than expected. Revenue was ahead of expectations, driven by a fast recovery in most markets, which led to better margins, and we ended the quarter with a strong cash position and ample liquidity. Net sales in the quarter were $1.2 billion, a reported and operational decrease of about 38% from the prior year, driven by the pandemic. We saw the deepest impact on our elected procedures and revenue in April, but then saw a rapid recovery with sequential improvement in May and June. While we're not at normal procedure volumes yet, we are encouraged by the trend since April, as all of our regions and businesses performed better than anticipated since our first quarter call. We will look more closely at our Q2 revenue trends, starting with regional performance and then pivot to our businesses. Moving forward, unless otherwise noted, my commentary will be on a constant currency basis. Beginning with Asia-Pacific, the region decreased about 18% in the second quarter versus the same period in the prior year. While China demonstrated sharp V-shaped recovery since April, posting improvement in May and growth in June, most other markets in the region continue to perform below normal run rates. In Japan, our largest market in Asia-Pacific, we've seen a different profile as that market never got to its trough levels experienced in China and was stable in Q2, operating at about 80% of normal run rates. Australia and New Zealand, our third largest market in Asia-Pacific, observed a sharp decline and a sharp recovery within Q2 and continues to make progress back to normalizations. many smaller markets within Asia Pacific continue to struggle with containing the virus and implementing effective policies. And accordingly, procedures were down substantially in the second quarter. But there's a wide disparity across the sub-markets within the region. But, as expected, a common theme is that we see improvement in the number of elective procedures when the infection rates are stable or declining and where there's a deference to physicians and hospitals to make treatment decisions based on the local situation. This holds true for other regions as well. Moving to EMEA, the region decreased 49% in the second quarter. As with other regions, we observed the deepest trough in April and then saw steady improvement through the quarter across all major markets, with the exception of the UK, where patients continue to be deferred at very high rates. Overall, developed markets with EMEA are recovering well. By the end of the second quarter, Germany had started to approach prior-year procedure volumes. France, Italy, and Spain also improved significantly through the quarter and showed the fastest recovery in the region in June. While not yet back to normalized levels, we are encouraged by this progress. Emerging markets in EMEA are improving, but generally continue to lag developed markets in that pace of recovery. Lastly, the Americas decreased 40% in the second quarter. As we talked about on our last quarterly call, the COVID-19 impact ramped up materially in mid-March with federal and state governments' guidance to defer elective procedures. April was a trough for the Americas, but we saw stronger-than-expected recovery in May and June as the U.S. states reopened. In the U.S., while there are variations week to week, to date we have seen approximately 50% of states at or above prior to case load levels, with 80% of states above 90% when compared to last year. While progress in the U.S. has been good, other markets within the Americas continue to struggle and operate well below normal levels. For example, if you strip out the rest of the Americas from the U.S., you would see that the U.S. hip and knee growth was actually about 200 to 300 basis points higher than the total Americas number. So clearly, non-U.S. markets in the Americas are still struggling creating a drag on overall regional performance. Importantly, in the U.S. and in other regions and markets, we are seeing second waves of steep infection growth. However, we clearly see that the healthcare systems in general are better equipped to address the pandemic, such that we're not seeing an erosion of elective procedures at the same level as observed in April. For example, in some of the hardest-hit counties within Texas, we continue to see procedure volumes at 80% or better, prior year volumes. We see a similar pattern in other severely hit states. Since the second quarter, in July, we have seen continued progress and sequential improvement in elective procedure trends. Next, let's turn to our businesses for Q2. Our global need business declined 47%. As we talked about last quarter, prior to the pandemic, we saw strong performance in this category, driven by improved operational execution and the continued positive impact of the persona revision launch. As Brian talked about a few minutes ago, Rose and me continues to be an important growth driver for us in the near term and the long term. And our ecosystem strategy in the knee business and other categories is really starting to take traction. A global hip business declined 31% in the second quarter. We continue to see our hip business recover faster than the knee business, pointing to somewhat less selective nature of these procedures. and we continue to see strong traction for our Avenir Complete launch. Sports extremity and trauma sales declined 29% in Q2. This decline was less pronounced than what we observed in large joints, primarily due to the non-elective nature of trauma. However, the trauma market continued to be pressured due to reduced activity levels related to widespread quarantine and stay-at-home orders. Central spine and CMFT sales declined 37% in the quarter. We've seen stronger recovery in spine due to recent new product introductions, including Tether. Also, much like our head business, spine procedures are seen as less elective by many physicians and patients, primarily due to the pain burden. Finally, our other category was down 44% versus the prior year. Looking beyond Q2, as you know, we withdrew our 2020 full-year financial guidance in April due to the uncertainty related to procedure volume uptake. The impact of COVID-19 continues to be fluid, and there are a number of market dynamics and variables that we are unable to reliably quantify at this time. As such, we will not be providing updated financial guidance for 2020, but we do want to share information and insights that may provide shaping of our revenue expectations for the remainder of the year. To give you a sense of the sequential improvement we saw through the second quarter, remember that on our first quarter call, we noted that that revenues were down about 70% in April across the full business. By the end of the quarter, in June, that decline was only 3.6% down. However, it's important to note that there was an additional selling day in June 2020 versus June 2019. After adjusting for the additional day in 2020, June was down 13.5%. There was no day rate impact on the full quarter. So, the key takeaway is, if the variables that Brian described earlier continue to play out as they are today, we expect the sequential improvement seen in Q2 to also continue through the back half of 2020, but likely at a more modest pace. Now, let's turn to P&L and liquidity. We've taken a disciplined and proactive approach to mitigate the earnings impact of the pandemic and to enhance our liquidity profiles. Results in the quarter were a little bit better than expected since our first quarter call, and we would expect margins, earnings, and cash flow to improve as our revenue profile improves moving forward. In terms of our second quarter results, we reported gap diluted loss per share for the quarter of $1 and adjusted diluted earnings per share of $0.05. Gap earnings per share in the second quarter were negative and lower than the prior year due primarily to the impact of the pandemic. and I will speak to that as part of our adjusted results. Adjusted earnings per share were lower than the prior year, driven by lower revenues and higher cost of goods. Adjusted gross margins were 65.5% for the second quarter due to less favorable mix and lower fixed cost absorption as a result of decreased production values. Adjusted operating expenses were lower due to reduced variable selling expense, the continued early impact of our restructuring program, and cost reductions we actioned to deal with the pandemic. As we previously discussed, we were able to flex quickly on COVID-19-related cost reductions in the first quarter by leveraging the restructuring programs already in place. Overall, adjusted operating margin for the quarter was 5.7%, substantially lower than the prior year, but, again, a bit better than what we expected on our first quarter call. Moving beyond operating margin, net interest expense of $54 million was down versus the prior year due to debt pay down in 2019. And our adjusted tax rate was 42.8% in the quarter. Our adjusted tax rate was distorted in the quarter due to discrete tax expenses on a small base of pre-tax income. We do not expect that trend to continue moving forward. Moving to cash and liquidity in the quarter. While free cash flow was negative $145 million, we ended Q2 with higher cash and cash equivalents of $713 million, further strengthening our liquidity position. Also, we continue to maintain $2.5 billion in additional liquidity through our credit facilities, which remain untapped. We believe we are well positioned from a capital structure standpoint. In terms of our P&L for the remainder of 2021, We expect that operating expenses will continue to ramp up in the second half of the year when compared to Q2 as we resume higher investment levels in R&D and commercial initiatives, in tandem with higher revenues. Interest expense will be a bit higher in the second half of the year versus the first half, driven by the refinancing of debt this year and the additional $1 billion facility put in place. For the adjusted tax rate, a full-year rate is expected to be about 100 basis points higher than what we originally guided in February, driven by a change in geographic mix of income due to COVID-19. Overall, we expect that margins, earnings, and cash flow will improve as our revenue profile improves. From a longer-term perspective, we remain committed to achieving at least 30% operating margin in 2023 as we continue to track well versus our restructuring plans. Summarized, our underlying business and our financial fundamentals remain strong, such that as the market continues to improve, we expect our financial performance will also improve. I continue to be extremely proud of how the ZD team has responded and performed over the past few months. We believe we're well positioned to address the current challenges as well as accelerate our growth profile over the long term. With that, I'll turn the call back over to Brian. All right, great. Thanks, Suki. In closing, you know, it's clear that the challenge of COVID-19 has been significant to ZB, to many, obviously. But we're also very encouraged by the early days of recovery, and I think really importantly, our ability to rise to that challenge as a team. And I'm going to leave you with three points from today's call that I hope you take away. You know, the first one is that the Q2 recovery clearly happened faster than expected, and we are encouraged as a result of that. But we are still cautiously optimistic about the performance in the back half of 2020, just due to the, you know, the variables associated with the pandemic that we still have to march through. And two, while our business has been impacted due to COVID-19, our strategic focus and our progress has not been disrupted. And if anything, this challenge has provided us with learnings that are enhancing strategic components of our business. And then three, we feel very confident about our underlying business strength, our core business strategy, and ZimberBio and its ability to drive long-term growth and value. I'm just going to take a minute before we close out the Q&A to say thank you to each and every one of our team members around the world. They're doing just a fantastic job. And your commitment and dedication to ZB enables us to deliver the value to our customers, to our patients, and to our shareholders. So with that, I'm going to turn the call back over to Carrie, and I'm looking forward to your questions.