But then if you take the derivative of a constant, well, that just disappears, so you don't see it when you look at the derivative. So we have to make sure that there might be a constant. And I have a feeling, based on the information that they've given us, we're going to make use of that constant. So let me rewrite f of x. So we know that f of x can be expressed as 24 divided by negative two. It's negative 12x to the negative two plus some constant. So how do we figure out that constant?