import java.util.Scanner;
import java.util.ArrayList;

public class Main {
	public static void main(String[] args){
		Scanner sc = new Scanner(System.in);

		int x = sc.nextInt();

		while (!isPrime(x)) x++;

		System.out.println(x);
	}

	public static boolean isPrime(int x) {
		if (x <= 1 ) return false;
		else {
			for (int i = 2; i * i < x; i++){
				if (x % 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