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,temp,min,d;

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

  if(x>=y)
    {
      min=y;
      temp=x%y;
    }
  else
    {
      min=x;
      temp=y%x;
    }

  for(d=min;d>0;d--)
    {
      if(temp%d==0 && min%d==0)
	{
	  break;
	}
    }
  printf("%d\n",d);
  return 0;
}