An old man is walking in Amsterdam and passes a hooker standing at her door. She says to him: "Hey Granddad, why don't we give it a try?"

He says: "No thank you. That is no longer possible for me."

It was a slow night, so the hooker says: "Oh, come on, what have we got to lose; let's give it a try."

So, they both go inside and he acts like the young man he used to be.

"Oh my goodness," says the hooker breathlessly afterward, "I thought you said sex was no longer possible for you."

Says the old man: "Oh, my body is still highly capable; it's the paying that is no longer possible."