import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		sc.close();
		int a = 1;

		while (a != 0) {
			a=0;
			for (int i = 2; i <= X / 2; i++) {
				if (X % i == 0) {
					a++;
				}
			}
			if (a != 0) {
				X++;
			}
		}
		System.out.println(X);
	}
}
/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