def int_input():
      inp = input('Please enter an integer: ')
      if inp.lstrip('-').rstrip().isdigit():
          return int(inp.rstrip())
      else:
          print('This was not an integer.')
          # return None # Passiert sonst implizit
          return int_input() # Rekursiver Aufruf
  
  
  a = int_input()
  b = int_input()
  c = int_input()
  print(a, b, c)
  # print(a + b if a and b else None, c)