import java.util.Scanner;

public class Main {

	public static void main(String[] args) {


		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();
		int answer = 0;
		if(x == 2) {
			System.out.println(2);
			return;
		}
		boolean flg = false;
		for(int i =x; ;i++) {
			for(int j = 2; j < i; j++) {
				if(i % j == 0) {
					break;
				}
				if(j == i-1) {
					flg = true;
				}
			}
			if(flg) {
				answer = i;
				break;
			}
		}
		System.out.println(answer);

	}
}
/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