text: #!/usr/bin/python3
  
  # Write a funciton named ack that evaluates the Ackermann function
  
  
  def ack(m, n):
      if not isinstance(m, int) and int(m) < 0:
          print("Value of m should be positive integer")
          return None
      if not isinstance(n, int) and int(n) < 0:
          print("Value of n should be positive integer")
          return None
      if int(m) == 0:
          return int(n) + 1
      if int(n) == 0:
          return ack(int(m)-1, 1)
      else:
          return ack(int(m)-1, ack(m, int(n)-1))
  
  
  if __name__ == '__main__':
      m = input("Please enter positive integer ")
      n = input("Please enter positive integer ")
      value = ack(m, n)
      print(value)
  