# maxn.py
# From Zelle p222
#

def maxn(ns):

# set the default
  max = ns[0]

  for n in ns:
    if n > max:
      max = n

  return max

def main():
  ns = input("Give me a list of numbers, eg 3,6,9,12,20: ")
  print "The max is: ", max(ns)


main()