import java.util.*;
public class Main {
	public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
      	int x = sc.nextInt();
        int num500 = x / 500;
      	int num50 = x % 500 / 5;
      	System.out.println(num500 * 1000 + num50 * 5);
    }
 }
/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