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(void){
  int x,y;
  int n;
  scanf("%d%d",&x,&y);

  if(x>y)n=y;
  else n=x;

  while(1){
    if(x%n==0 && y%n==0)break;
    n--;
  }
  printf("%d\n",n);
  
  return 0;
}