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>
main()
{
   long int x,y,big,i,small;
    scanf("%ld%ld",&x,&y);
    if(x>y)
       {big=x;
        small=y;}
    else
       {big=y;
        small=x;}
    for(i=small;i<=big;i--)
    {
        if((x%i==0)&&(y%i==0))
        {   printf("%ld\n",i);
        break;}

    }

}