public class Solution {
    public static void main(String[] args) throws Exception {
        BufferedReader reader = new BufferedReader(new InputStreamReader(System.in));
        String a = reader.readLine();
        int num = Integer.parseInt(a);

        if (num>+0)
        {
            num=num*2;
        }
        else {
            num=num+1;
        }
        System.out.println(num);

        if (num == 0)
        {
            num=num;
            System.out.println(num);
        }
    }
}