And in a few other things, but mainly permutations and combinations. So let's review a little bit. We've said that, hey, you know, if we have n things and we want to figure out the number of ways to permute them into k spaces, it's going to be, it's going to be n factorial over n minus, over n minus k factorial. Now we've also said that if we had, if we had n things that we want to permute into n places, well this really should just be n factorial. The first place has, you know, let's just do this. So this is the first place, this is the second place, this is the third place, all the way you get to the nth place. Well, there would be n possibilities for who's in the first position or which object is in the first position.