What is the joke that the fortune teller lied to you?

Young man: Fortune teller, please calculate how much money I have. If you guess, I'll let you calculate something else. Fortune teller: If my calculation is correct, you should have no money with you today. Young man: Your calculation is really accurate. Please help me calculate the others. Fortune teller: Shit, I don't even have money, and you want me to tell your fortune.