package yukicoder;

import java.util.Scanner;

public class N192 {
	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;
				}
			}
		}
	}
}