If each of 5 adult college students desires a shot of tequila, then, to determine who will pay for the shots, each one of them individually flips a fair coin simultaneously with the others. If all the coins but one show the same face, then the student with the different result is the one who pays. If any other combination of heads and tails shows on the 5 coins, then all of the students flip again. Let X = number of flips (per student) to decide who pays. Compute the pmf of X.