def interact():
    while True:
      try:
        user_input = int(input('Please input an integer:'))
      except ValueError:
        print('Please input only intergers')
        raise
      else:
        print('{} is {}.'.format(user_input, 'even' if user_input % 2 == 0 else 'odd'))
      finally:
        user_input = input('Do you want to play again? (y/N):')
        if user_input != 'y':
          print('Goodbye.')
          break

interact()