And this is a little bit of an aside, but the notation for the set of integers tends to be a bold Z. And it's Z for Zoll from German for apparently integer. And the bold is this kind of weird looking, they call it blackboard bold. And it's what mathematicians use for different types of sets of numbers. And in fact, I'll do a little aside here to do that. So for example, they might say, they'll write R like this for the set of real numbers, real numbers. They'll write a Q in that blackboard bold font.