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 main(){
	int x, y;
	int tmp, gcd;
	int i=1;
	
	scanf("%d%d",&x,&y);
	if(x>y){
		if (x > 10000) {
			tmp = x;
			x = y;
			y = tmp % x;
		}
	}

	else if (x == y);
	
	else {
		tmp = x;
		x = y;
		y = tmp;

		if (x > 10000) {
			tmp = x;
			x = y;
			y = tmp % x;
		}
	}

	while(i<=x || i<=y){
		if(x%i==0 && y%i==0){
			gcd = i;
		}
		i++;
	}

	printf("%d\n",gcd);

	return 0;
}