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 Python (judge verdict: Memory Limit Exceeded)

x, y = map(int, raw_input().split())
min_xy = min([x, y])
gcd = 0
for i in range(1, min_xy+1):
    if (x % i == 0) & (y % i == 0):
        gcd = i
print gcd