So really the interesting part is during the fourth minute. So let me just draw a little number line here and we can think about what the fourth minute looks like. Or actually, let me just draw the whole thing. So let's say this is r of t right over there. We could say y is equal to r of t. And this is t. And let's see, the first minute goes from zero to one, second minute goes from one to two, third minute goes from two to three, fourth minute goes from three to four. The rate function, this actually just looks like a straight up linear rate function, looks something like this. And so what is the fourth minute?