import java.util.*;

public class Main {
	static Scanner sc = new Scanner(System.in);
	public static void main(String[] args) {
		int n = sc.nextInt();
		int a = n-100;
		int b = n+100;
		for (int i=a; i<=b; i++) {
			boolean boo = isPrime(i);
			if (boo==false && i!=1) {System.out.println(i); break;}
		}
	}
	public static boolean isPrime(int num) {
	    if (num < 2) return false;
	    else if (num == 2) return true;
	    else if (num % 2 == 0) return false;
	    double sqrtNum = Math.sqrt(num);
	    for (int i = 3; i <= sqrtNum; i += 2) {
	        if (num % i == 0) {return false;}
	    }
	    return true;
	}
}