input: def max_of_three(a: int, b: int, c: int) -> int:
      """Return the maximum of three numbers.
      >>> max_of_three(3, 4, 5)
      5
      >>> max_of_three(10, 2, 9)
      10
      >>> max_of_three(8, 8, 8)
      8
      """
      if a > b and a > c:
          return a
      elif b > a and b > c:
          return b
      else:
          return c
output:     if a > b and a > c:
          return a
      elif b > a and b > c:
          return b
      else:
          return c