'''
    CS5001
    Fall 2018
    Sample code we cooked up in class --
    just playing with the basic stack operations
'''

from mystax import Stack

def main():
    s = Stack()
    s.push(15)
    s.push(18)
    s.push(21)
    print(s.top())
    s.pop()
    print(s.top())

main()