import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

import static java.lang.System.in;

public class Main {
    public static void main(String[] args) throws IOException {
        BufferedReader reader = new BufferedReader(new InputStreamReader(in));
        int N = Integer.parseInt(reader.readLine());
        int compositeNumber;
        if (N % 2 == 0) {
            compositeNumber = N;
        } else {
            compositeNumber = N + 1;
        }
        System.out.println(compositeNumber);
    }
}