It's going from increasing to decreasing. Increasing to decreasing at either of the points. Or you could say that the first derivative is going from positive to negative. So if you look at this interval right over here, g prime is greater than zero, and then over the next interval, when you're decreasing, g prime would be less than zero. So what we really need to think about is when does g prime, so let me see, relative, we care about relative maximum point, and so that's essentially asking when does g prime go when does g prime go from positive to negative? From, I wrote frore, from g prime greater than zero to g prime less than zero. And the values that we could look at, or the points, are our critical points.