package no192;

import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int n = sc.nextInt();
		for(int i=n+100;i>=n-100;i--) {
			for(int j=2;j<i;j++) {
				if (i % j == 0) {
					System.out.println(i);
					return;
				}
			}
		}
		System.out.println("!?");
	}
}