подскажите в чем проблема?
package com.javarush.task.task14.task1420;
/*
НОД
*/
import java.io.BufferedReader;
import java.io.InputStreamReader;
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
int a = Integer.parseInt(reader.readLine());
int b = Integer.parseInt(reader.readLine());
if (a <= 0 || b <= 0) throw new Exception();
while (a != b && b != 0){
if (a > b) a %= b;
else b %= a;
}
System.out.println(a + b);
}
}