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, z, d, f;
   int c = 1;
   int e = 0;

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

   if(x < y) {
      z = x;
      x = y;
      y = z;
   }

   while(x % 10 == 0 && y % 10 == 0) {
      x /= 10;
      y /= 10;
      e++;
   }
      

   for(d = y; d >= 2; d--) {
      if(y % d == 0 && x % d == 0) {
         c = d;
         break;
      }
   }

   for(f = e; f > 0; f--) {
      c *= 10;
   }

   printf("%d\n", c);
   return 0;
}