Hallo, kann mir bitte jemand sagen was ich hier falsch mache?
package de.codegym.task.task04.task0412;
/*
Positive und negative Zahlen
*/
import java.io.*;
public class Solution {
public static void main(String[] args) throws Exception {
BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
String a = reader.readLine();
int na = Integer.parseInt(na);
System.out.println(na);
if ( na < 0) System.out.println( na + 1)
else if (na == 0) System.out.println(0)
else (na > 0) System.out.println( na * 2)
}
}