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 <stdio.h>

int gcd(int x, int y) {
	int i;
	for (i = x; i > 0; i--) {
		if (x % i == 0 && y % i == 0) {
			break;
		}
	}
	return i;
}

int main(void) {
	int a, b;
	scanf("%d %d", &a, &b);

	if (a < b) {
		printf("%d\n", gcd(a, b));
	} else {
		printf("%d\n", gcd(b, a));
	}
	return 0;
}