import java.util.*;
public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long x= sc.nextLong();
        long happinessCount = 0;
        while (x>4){
            if(x>=500){
                happinessCount += 1000;
                x -= 500;
            }else {
                happinessCount += 5;
                x -= 5;
            }
        }
        System.out.println(happinessCount);
    }
}
/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