import java.util.Scanner;

public class Main {
  public static void main(String[] args) {
    Scanner sc = new Scanner(System.in);
    long X = sc.nextLong();
    sc.close();

    for (long i = X; i < 100007; i++) {
      if (isPrimeNumber(i)) {
        System.out.println(i);
        return;
      }
    }
  }

  private static boolean isPrimeNumber(long num) {
    if (1 >= num) return false;
    if (2 == num) return true;
    long n = (long) Math.sqrt(num);
    for (long i = 2; i <= n; ++i) {
      if (0 == (num % i)) 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