import java.util.Scanner;
public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		int sosu = scan.nextInt();

		while(!hantei(sosu)) {
			sosu++;
		}
			System.out.println(sosu);
		scan.close();

	}

	public static boolean hantei(int s) {


		if(s >= 2) {
		for(int i=2;i*i<=s;i++) {

			if(s%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