3 men go to a hotel, the room price is 15 dollars so each man pays 5 bucks, but then the receptionist realizes there is a discount so the room is only 10 dollars, so she hands back 5 dollars, so each man decides to take a dollar each and give the receptionist a 2 dollar tip, now if you add what I have said up, you will realize there is a dollar missing, please someone help me figure this out, its been in my mind for days now