Find the greatest common divisor of two positive integers. The integers can be large, so you need to find a clever solution. 
The inputs `x` and `y` are always greater or equal to 1, so the greatest common divisor will always be an integer that is also greater or equal to 1.
def mygcd(x,y):
    """Euclidean algorithm."""
    reminder = x%y
    if reminder == 0:
        return y
    else:
        return mygcd(y,reminder)
def mygcd(x,y):
    """Euclidean algorithm."""
    reminder = x%y
    if reminder == 0:
        return y
    else:
        return mygcd(y,reminder)