import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class Main {
	public static void main(String[] args) throws IOException {
		BufferedReader r = new BufferedReader(new InputStreamReader(System.in));
		String s = r.readLine();
		int num = Integer.valueOf(s);

		while (true) {
			boolean flag = isSosu(num);
			if (flag) {
				System.out.println(num);
				r.close();
				return;
			}
			++num;
		}
	}

	public static boolean isSosu(int value) {
		for (int i = 2; i < value; ++i) {
			if (value % 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