All right, F of B. And we assume that we have a continuous function here. So the graph, I could draw it from F of A to F of B, from this point to this point without picking up my pencil. From this coordinate, A comma F of A, to this coordinate, B comma F of B without picking up my pencil. Well, let's assume that there is some L that we don't take on. Let's say there's some value L right over here, and we never take on this value. This continuous function never takes on this value as we go from X equaling A to X equal B.