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,cnt=0,n,i=1;
    scanf("%d%d",&x,&y);
    if(x <= y){
        n = y;
    }else {
        n = x;
    }
    while(1){
        if(x%i==0&&y%i==0){
            cnt = i;
        }
        if(n == i) break;
        i++;
    }
    printf("%d\n",cnt);
    return 0;
}