A: Excuse me! I need a ticket.

B: You owe me a dollar.

A: I already put one in!

B: Yes, and you owe me another.

A: The counter says fare is one dollar!

B: The fare counter tells how much money you've inserted.

A: I don't understand.

B: It reads one dollar because you put in a dollar.

A: How do I know I've paid the fare?

B: The counter will go back to zero.

A: Oh, I see what you mean.

B: Now that you've paid your two dollars, here's your ticket.