So this is approximately, approximately 48.544 cubic feet. And now let's see if there's any point in between where w hits a local maximum point or a local minimum point, I should say. I think I said a local maximum earlier on. I should say a local minimum point. And so if it's at a local minimum or maximum point, really, the derivative of w is going to be zero. So let's see, at what t do we get a zero derivative? So w prime of t. Well, the derivative of a constant with respect to t is zero.