import java.util.*;

public class Main {
    public static void main(String[] args){
        Scanner scan = new Scanner(System.in);
        int x = scan.nextInt();
        for(int i = x; i <= Math.pow(10, 9); i++){
            if(isPrime(i)){
                System.out.println(i);
                return;
            }
        }
        scan.close();
    }
    
    public static boolean isPrime(int n){
        for(int i = 2; i <= Math.sqrt(n); i++){
            if(n % i == 0) return false;
        }
        return true;
    }
}

/tmp/hf-datasets-cache/medium/datasets/42704881117311-config-parquet-and-info-qiankunmu-Project_CodeNet-896c9d36/hub/datasets--qiankunmu--Project_CodeNet_Python800_and_Java250/snapshots/c899fde44a77ba1cc14973ed3de064e4ff3aadc7/Project_CodeNet_Java250.tar.gz