def euklid_ggt(x, y):
    while x > 0:
        if x < y:
            (x, y) = (y, x)
        x -= y
    return y


if __name__ == "__main__":
    print(euklid_ggt(12, 8))
    print(euklid_ggt(8, 12))
    print(euklid_ggt(12, 12))
    print(euklid_ggt(12, 1))
    print(euklid_ggt(1, 12))
    print(euklid_ggt(1, 1))