import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner koko = new Scanner(System.in);
        int n= koko.nextInt();
        if(n%2==0){
            System.out.println(n);
        }
        if(n%2==1){
            System.out.println(n+1);
        }
    }
}