import java.util.Scanner;
    public class Main{
        public static void main(String[] args) {
            Scanner in=new Scanner(System.in);
            long num=in.nextLong();
            long tk=0;
            long pchso=num/500;
            tk=pchso*1000;
            int baki=(int) (num%500);
            long pach=baki/5;
            tk=tk+(pach*5);
            System.out.println(tk);
        }
    }
/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