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, i, j, n;

   scanf("%d %d", &x, &y);

   n = 10*10*10*10*10*10*10*10*10;

   for(i=n; i>=1; i--)
      if(x%i == 0)

   for(j=n; j>=1; j--)
      if(y%j == 0)

   if(i == j){
      printf("%d\n", i);
      return;
   }

   return 0;
}