And then the function starts increasing again, all the way until this point right over here. It hits zero, and then it goes, and the function starts decreasing. So we're going to, just this first constraint right over here, tells us it's going to be something in this interval right over there. And then they say where the second derivative is less than zero. So this means that the slope itself, whether it's positive or negative, that it's actually decreasing. We are going to be concave downwards right over here. The slope itself, it could be positive, but it'll be coming less and less and less positive.