# roll dice and keep rolling until you quit
#
# load the random class
#
import random
#
# assume user wants to roll the dice
#
rollem = "yes"
#
# now roll repeatedly until done
#
while rollem == "yes":
    # it's a 20-sided die; note we add 1 because the random number
    # generated is between 0 and 19 (20-1) inclusive; by adding 1,
    # we will print a number between 1 and 20
    die = random.randrange(20) + 1
    print "You rolled a 20 sided die and", die, "came up.",
    #
    # see if she wants to go again
    #
    rollem = raw_input("Again (yes/no)? ")
    while rollem != "yes" and rollem != "no":
        # sorry, I don't understand that ...
        rollem = raw_input("I only understand 'yes' or 'no'. Again (yes/no)? ")