import java.io.*; public class Solution { public static void main(String[] args) throws Exception { BufferedReader buffer = new BufferedReader(new InputStreamReader(System.in)); String num = buffer.readLine(); int number = Integer.parseInt(num); if(number>0) { number = number*2; System.out.println(number); } if(number<0) { number = number + 1; System.out.println(number); } if(number==0) { System.out.println(0); } } }