The number 7, it's an A and it's in the set of all things in the universe that are neither a 0 or a blue. So let's put a 7 there. Negative 5 also meets that constraint. A 0 does not meet that constraint. A 0 is an A, but it's not in the set of all things in the universe that are neither a 0 or a blue, because it is a 0. So we're not going to throw a 0 in there. And then a 13 is an A, and it's in the set of all things in the universe that are neither a 0 or a blue.