import java.util.*;
 public class Main {
	public static void main(String[] args){
      Scanner sc = new Scanner(System.in);

      int X = sc.nextInt();
      int sum = 0;

      while(X >= 500){
         X -= 500;
         sum += 1000;
      }

      while(X >= 5){
         X -= 5;
         sum += 5;
      }

      System.out.println(sum);
   }
 }

/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