So here is a few exercises that you can use to test your understanding material in this section. So, first one is just a calculation. So, how many people would you think, if you were a paranoid professor and you had a big class, how big would the class be to be 99% sure that if you ask everybody in the class you're going to find two that have the same birthday? So that's just a fun calculation. So this next one is kind of a commonatorial thing. It's actually the basis for Kunuth's analysis of linear probing. And it ties together uh,some of the calculations that we did in this section having to do with Kali trees. And it's actually easier than it looks. So it's, proving this generalization of the binomial theorem, due to, Abel. And it's worthwhile doing this, this calculation. And then, here's an exercise that isn't in the book. That, but it should be there. So I numbered it, number 99. And it's to show that the probability. If you take a random mapping of size n. What's the probability that, it doesn't have any singleton cycles. Nothin' that maps to itself. Amazingly it turns out to be N over E the same as the derangement problem for permutations. There's no good reason that these things should be the same but it turns out not to be the same. So that's a, a nice exercise for, for you to take a look at. So, to finish up, read that part of the text. Good idea to run empirical tests to see if, Kunuth's analysis works, and you'll find that it does. And it's also a good idea to, take a look at properties of mappings and check that, the, analysis, works as well. And then maybe write up those solutions to, those exercises. That's, the, end of analytic combinatorics, part 1. We've done a pretty full survey of basic techniques, introduced analytic combinatorics and shown how it applies to the study of basic combinatorial structures like trees, permutations strings words and mapping. We, we hope that as many of you are interested enough in the, in the problems that we've looked at to sign up for Analytic Combinatorics part 2, which'll start soon, thanks.