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,smo,big,arr;
  scanf("%d,%d",&x,&y);
  if(x>=y){
    smo=y;
    big=x;
  }
    else{
      smo=x;
      big=y;
    }
    while(1){
      arr=big%smo;
      if(arr=0)break;
      smo=big;
      arr=smo;
    }
    printf("%d\n",smo);
    return 0;
}