import java.util.*;
class Main{
  public static void main(String args[]){
    Scanner sc = new Scanner(System.in);
    long X = sc.nextLong();
    long answer = 0;
    
    for(long i=X;i<100000000;i++){
      int count = 0;
      for(long j=2;j*j<=i;j++){
        if(i%j==0){
          count++;
          break;
        }
      }
      if(count==0){
        answer = i;
        break;
      }
    }
    System.out.println(answer);
  }
}
/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