package com.codegym.task.task04.task0412;
/*
Positive and negative numbers
*/
import java.io.*;
import java.io.BufferedReader;
public class Solution {
public static void main(String[] args) throws Exception {
//write your code here
//InputStream inputStream = System.in;
// Reader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader buffer= new BufferedReader(new InputStreamReader(System.in));
String name = buffer.readLine();
String aNum = buffer.readLine();
int number= Integer.parseInt(aNum);
if( number < 0){
number = number*2;
System.out.println (number);
}
else {
if (number < 0){
number =-1;
System.out.println(number);
}
}
if (number<0){
number =0;
System.out.println(0);
}
}
}