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, i;
   int d = 1;
   scanf("%d %d", &x, &y);

   for(i = 2; i <= x; i++){
      if((x % i == 0) && (y % i == 0))
         d = i;
   }
   printf("%d\n", d);

}