Thanks Simeon. Good morning. You know, if you think about the margin that we saw, particularly after our store opening periods from June through December, you know, we used the word exceptional purposefully that they were very high margins, there was a lot of great work being done in our stores, demand was high, there was some stimulus benefit, we were seeing mixed benefits in terms of a little more eyeglass and contact lens versus historical patterns. We were seeing the stimulus benefits lift tickets, and that's just customers, you know, picking out incremental things that they wanted to add, because they could. We were in a fairly low to moderate position in terms of our typical advertising spend. We obviously weren't traveling, and due to the double digit comps, we were really well beyond our comp leverage point. So, you know, I would say like this, if we had another period where we were 2 x or more on our comp leverage point and found that advertising wasn't necessary that could be a nice benchmark. I don't think there's anything. So, elements of that are going to moderate back to a norm. But again, our norm has been improving, we, we lifted operating margins, 30 basis points from 2018 to 2019, another 20 from 2019 to 2020. You know, management team is focused on that. We hope to, you know, have a shot at delivering some more that lift again, but I do want to cordon off those months of June through December as being just outside of the norm. Now, in the fourth quarter, we did see advertising moderate back to more normal levels. And it was a great high watermark. I don't know if that makes sense in the next two years to be able to shoot for that, but I can promise you that management is always looking for ways to improve margins without you know, providing any negative consequences for the mission of the company.