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 i,x,y,z1,z2,ans;
  ans=1;
  scanf("%d%d",&x,&y);
  if(x>y){z1=y;z2=x;}
  else {z1=x;z2=y;}
  for(i=2;i<=z1;i++)
    if(z1%i==0&&z2%z1%i==0)ans=i;

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

return 0;
}