'''simple docstring'''


from functools import lru_cache

@lru_cache
def   A_      (       SCREAMING_SNAKE_CASE_						)			->int:
  if num < 0:
    raise ValueError("""Number should not be negative."""						)

  return 1 if num in (0, 1) else num * factorial(num - 1						)


if __name__ == "__main__":
       import doctest

       doctest.testmod()


'''simple docstring'''


def   A_      (       SCREAMING_SNAKE_CASE_						)			->bool:
  if number < 0:
    raise ValueError("""number must not be negative"""						)
  return number & (number - 1) == 0


if __name__ == "__main__":
       import doctest

       doctest.testmod()

