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: Accepted)

#include<stdio.h>

int main(){

  int x,y,k,i,j,v;

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


  if(x>=y){
    if(x==y) v=x;

    k=x%y;
      for(i=1;i<=k;i++){
	if(y%i==0 && k%i==0) v=i;
    }
  }
  
  else if(y>x){
    k= y%x;
    for(i=1;i<=k;i++){
      if(x%i==0 && k%i==0) v=i;
    }
  }

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

  return 0;
}