import java.util.Scanner;

public class Main {
	static int p[][];

	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int x = sc.nextInt();

		while(!IsPrime(x)) {
			x++;
		}

		System.out.println(x);

        return;
    }

	static boolean IsPrime(int n) {
		if (n == 2) return true;
		else if (n%2 == 0) return false;
		double sqrtNum = Math.sqrt(n);
		for (int i=3; i<=sqrtNum; i+=2) {
			if (n%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