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 JAVA (judge verdict: Wrong Answer)

import java.util.*;

public class Main{
    public static void main(String[] args){
	int n=1;
	Scanner a = new Scanner(System.in);
	int x = a.nextInt();
	int y = a.nextInt();
	for(int i=2; i<x && i< y; i++){
	    if(x%i == 0 && y%i == 0){
		n = i;
	    }
	}
	System.out.println(n);
    }
}