ticketsLeft = 100

while ticketsLeft > 0:
    print('# of tickets')
    ticketsNow = int(input())
    if ticketsLeft == 0:
        break
    if ticketsNow > ticketsLeft:
        print('there are only ' + str(ticketsLeft) + ' tickets left')
        continue
    if ticketsNow <= int(4):
        print('you bought ' + str(ticketsNow) + ' tickets')
        ticketsLeft = ticketsLeft - ticketsNow
    else:
        print('You can only purchase 4 tickets at a time')
print('no tickets left')