в 13 строке?
package com.javarush.task.task14.task1420;
import java.io.*;
import java.math.*;
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
try
{
int a = Integer.parseInt(reader.readLine());
int b = Integer.parseInt(reader.readLine());
if (a<=0||b<=0) throw new MyIncredibleException ();
}
catch (MyIncredibleException e)
{
System.out.println (e);
}
BigInteger b1 = BigInteger.valueOf(a);
BigInteger b2 = BigInteger.valueOf(b);
BigInteger gcd = b1.gcd(b2);
System.out.println (gcd.intValue());
}
public class MyIncredibleException extends Exception {
}
}