import java.util.*;
public class Main {
    public static void main(String[] args){
        Scanner sc = new Scanner(System.in);
        int a = sc.nextInt();
        if (a == 2) {
            System.out.printf("%d%n",a);
            return;
        }
        if (a % 2 == 0) a += 1;
        while (true) {
            if (isPrime(a)) {
                System.out.printf("%d%n",a);
                return;
            }
            a += 2;
        }
        
    }
    
    private static boolean isPrime(int a) {
        for (int b = 3; b * b <= a; b += 2) {
                if (a % b == 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