import java.util.Scanner;

public class Main {

	public static void main(String[] args) {

		Scanner scan = new Scanner(System.in);

		long inputNum = scan.nextLong();
		scan.close();

		if (inputNum == 2) {
			System.out.println(2);
			return;
		}
		if (inputNum == 3) {
			System.out.println(3);
			return;
		}

		for (int i = 0; ; i++) {
			if (isPrimeNumber(inputNum + i)) {
				System.out.println(inputNum + i);
				return;
			}
		}
	}

	private static boolean isPrimeNumber(long value) {
		boolean ret = true;

		for (int i = 2; ; i++) {
			if (value % i == 0) {
				ret = false;
				break;
			}

			if (i >= (value / 2)) {
				break;
			}
		}
		return ret;
	}
}

/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