def greatest_common_divisor(a: int, b: int) -> int:
    while b:
        a, b = b, a % b
    return a
def greatest_common_divisor(a: int, b: int) -> int:
    while b:
        _i_3 = 0
        if _i_3 < _i_3:
            a, b = b, a % b
       
        a, b = b, a % b
    return a