def input_int(prompt):
    while True:
        var = input(prompt)
        if var.isdigit():
            return int(var)
        print("Input a valid number!")

x = input_int('Enter x:')
y = input_int('Enter y:')

while True:
    k = x % y
    if k == 0:
        break
    (y, x) = (x, k)

print("Result: " + str(y))