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: Accepted)

import math
def div(x, y): #x>y
    A = 1
    for i in range(1, int(math.sqrt(x))+1):
        if x % i == 0 and y % i == 0:
            A = max(A, i)
        j = int(x/i)
        if x % j == 0 and y % j == 0:
            A = max(A, j)
    return A
x, y = map(int, input().split(" "))
print(div(x,y))