import java.util.*;

public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        int N = sc.nextInt();
        int n = N - 100;
        int d = 0;
        if(N % 2 == 0){
            System.out.println(N);
        }
        while(d == 0){
            if(n % 2 == 0&&n!=2){
                System.out.println(n);
                d++;
            }else{
                n++;
            }
        }
    }
}