import java.util.Scanner;


public class Main {

    public static void main(String[] args) {
        Scanner sc=new Scanner(System.in);
        int n = sc.nextInt();
        for (int i = Math.max(3, n-100); i <= n + 100; i++) {    
            for (int j = 2; j*j <= i; j++) {
                if(i%j==0){
                    System.out.println(i);
                    return;
                }
            }            
        }
    }

}