So I'm assuming you've had a go at it. So for each of these, so for the first, so for the first rectangle over here, we're going to multiply two times the height. So the height right over here is one, and this is the first rectangle, so you might be tempted to say times f of n. But then that breaks down as we go into the second rectangle. The second rectangle, the two still applies. This two is the width of the rectangle. But now we want to multiply it times f of three, not f of two. So this f of n isn't going to, this f of n isn't going to, isn't going to pass muster.