import java.util.Scanner;

public class Main{
  public static void main(String ars[]){
    Scanner sc = new Scanner(System.in);
    int a = sc.nextInt();
    int ans = 0;
    for(int i = a;;i++){
      for(int j = 2;j <= i;j++){
        if(i % j == 0 && j != i) break;
        if(j == i) ans = i;  
      }
      if(ans != 0) break;
    }
    System.out.println(ans);
  }
}
/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