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 GCD,x,y,n,i;

    scanf("%d %d",&x,&y);
    if(x > y) n = y;
    else n = x;

    for(i = 1 ; i<= n ; i++)
      {
	if(x%i == 0 && y%i == 0) GCD = i;
		
      }

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

    return 0;
}