import java.io.*;
import java.util.*;


public class Main {
    public static void main (String[]args)throws IOException {
        Scanner scanner = new Scanner(System.in);
        long x = scanner.nextLong();
        long answer=0;
        long bigYen=(x-(x%500))/500;
        answer+=bigYen*1000;
        long extra=x%500;
        extra-=extra%5;
        answer+=extra;
        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