Some people will call this N choose K. They'll also write it like this. N choose K, especially when they're thinking in terms of binomial coefficients. But I got into kind of an abstract tangent here when I started getting into the general formula, but let's go back to our example. So in our example, we saw there was 360 ways of seating six people into four chairs. But what if we didn't care about who's sitting in which chairs, and we just want to say, how many ways are there to choose four people from a pool of six? Well, that would be, that would be how many ways are there, so that would be six, how many combinations, if I'm starting with a pool of six, how many combinations are there, how many combinations are there for selecting four? Or another way of thinking about it is, how many ways are there to, from a pool of six items, people in this example, how many ways are there to choose four of them?