def GCD(a, b):
    if a % b == 0:
        return b
    else:
        GCD(b, a % b)


def main():
    num1, num2 = eval(input("Enter two numbers: "))
    if num1 < num2:
        num1, num2 = num2, num1
    print("GCD :", GCD(num1, num2))


main()
