import java.util.Scanner;

public class Main {

	public static void main(String[] args) {
		// TODO 自動生成されたメソッド・スタブ

		Scanner sc = new Scanner(System.in);
		//入力表示

		int X = sc.nextInt();
		int a = X;

		while (!determine(a)) {
			a++;
		}
		System.out.println(a);
	}

	public static boolean determine(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