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 C++ (judge verdict: Time Limit Exceeded)

#include<iostream>
using namespace std;
unsigned int x, y;
int main() {
	int max;
	cin >> x >> y;
	if (x <= y) {
		for (int i = x; i > 0; i--) {
			if (x%i == 0 && y%i == 0) {
				cout << i << endl;
				goto end;
			}
		}
	}
	else {
		for (int i = y; i > 0; i--) {
			if (x%i == 0 && y%i == 0) {
				cout << i << endl;
				goto end;
			}
		}
	}
end:;
}