import java.util.Scanner;
import java.math.BigInteger;

public class Main {
  public static void main(String[] args) {
    Scanner in = new Scanner(System.in);
    BigInteger b = in.nextBigInteger();
    if(b.isProbablePrime(70)==true)
      System.out.println(b);
    else
      System.out.println(b.nextProbablePrime());
  }
}
/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