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,a,b,answer,i;

  i = 0;

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

  while(i < x && i < y){

    i = i + 1;

    a = x % i;

    b = y % i;

    if(a == 0 && b == 0){

      answer = i;

    }

  }

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

  return 0;

}