So one way of thinking about it, like we just said, these are all of the elements that are in set A that are not in set B. Another way you could think about it is, these are all of the elements that are not in set B but also in set A. So let me make it clear. You could view this as B subtracted from A, or you could view this as the relative complement of set B in A. And we're going to talk a lot more about complements in the future, but the complement is the things that are not in B. And so this is saying, look, what are all of the things that are not in B? So you could say, what are all of the things not in B but are in A?