Well, let's think about it. 365 factorial is what? 365 factorial is equal to 365 times 364 times 363 times all the way down to 1, right? You just keep multiplying, it's a huge number. Now, if I just want the 365 times the 364 in this case, I have to get rid of all of these numbers back here. So one thing I could do is I could divide this thing by all of these numbers. So 363 times 362 all the way down to 1.