def gcd(a, b):

    """Returns the Greatest Common Divisor of the two integers

    passed as arguments.

    Args:

      a: an integer

      b: another integer

    Returns: Greatest Common Divisor of a and b

    >>> gcd(48, 64)

    16

    >>> gcd(44, 19)

    1

    """

    if b == 0:

        return b

    return gcd(b, a%b)

if __name__ == "__main__":

    import doctest

    doctest.testmod()