#def not_only_sum()

import math
def not_only_sum(*args, mode):
  s = 0
  m = 1
  s_a = 0
  if mode == 'sum':
    for i in args:
      s += i
    return s
  elif mode == 'average':
    for i in args:
      s += i
    return s/len(args)
  elif mode == 'mult':
    for i in args:
      m *= i
    return m
  else:
    if mode == 'sdev':
      for i in args:
        s += i
      s2 = s/len(args)
      for j in args:
        s_a += (j - s2) ** 2
      s_k = s_a/len(args)
      return math.sqrt(s_k)
print(not_only_sum(1, 2, 3, 4, 5, mode = 'sdev'))