"""GCD calculator."""

def gcd(m,n):
    """Calculate the greatest common divisor of two numbers.

    Args:
      m (int): the first number
      n (int): the second number

    Returns:
      int: the greatest common divisor of m and n

    """
    pass  # TODO: replace by your implementation


def cli_gcd():
    """Read numbers from standard input and print out their gcd."""
    pass # TODO: replace by your implementation


if __name__ == '__main__':
    cli_gcd()