import java.util.Arrays;
import java.util.Scanner;

public class Main {
	public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int prime[] = new int[100004];
		Arrays.fill(prime, 1);

		for (int i = 2; i <= 100003; i++) {
			int tmp = i;
			int next = i * 2;
			int j = 3;
			while (next <= 100003) {
				prime[next] = 0;
				next = tmp * j;
				j++;
			}
		}

		for (int i = X; i <= 100003; i++) {
			if (prime[i] == 1) {
				System.out.println(i);
				break;
			}
		}
	}
}
/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