Problem:
Greatest Common Divisor

Write a program which finds the greatest common divisor of two natural numbers a and b

Input

a and b are given in a line sparated by a single space.

Output

Output the greatest common divisor of a and b.

Constrants

1 ≤ a, b ≤ 109

Hint

You can use the following observation:

For integers x and y, if x ≥ y, then gcd(x, y) = gcd(y, x%y)

Sample Input 1

54 20

Sample Output 1

2

Sample Input 2

147 105

Sample Output 2

21

Solution in Python3 (judge verdict: Time Limit Exceeded)

a, b = map(int, input().split())
c = []
if a > b:
    a, b = b, a
while True:
    for i in range(a):
        x = i + 2
        if a%x == 0:
            if b%x == 0:
                c.append(x)
                a = a//x
                b = b//x
                break
    if i == a-1:
        break
s = 1
for j in c:
    s = s * j
print(s)