package yukicoder;

import java.util.Scanner;

public class Yuki12 {
    
    public static void main( String[] args ) {
        
        Scanner scan = new Scanner(System.in);
        int n = scan.nextInt();
                
        for ( int i = (n - 100); i <= n + 100; i++ ) {
            
            if(i<=3){
                continue;
            }
                        
            if(check(i,n)){
                break;			
            }
        }
    }
    
    public static boolean check(int num,int n) {
        
        for(int i=1; i <= num; i++ ) {
            
            if (i <= 3){
                continue;
            }
            
            if (i == n - 100 || i == n + 100){
            	System.out.println(num + 1);
                return true;
            }
            
            if (num%i == 0){
                System.out.println(num);
                return true;
            }
        }
        return false;
    }
}