import java.util.*;

public class Main {
    public static void main(String[] args){
 
	Scanner sc = new Scanner(System.in);
    int X = sc.nextInt();
   
	int gohyaku = X/500;
	int goen =(X-(gohyaku*500))/5;

      System.out.println(1000*gohyaku + 5*goen);

    }
}
/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