import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);

        long x = scan.nextLong();
        long u = 0;
        while(x >= 500) {
            x -= 500;
            u += 1000;
        }
        while(x >= 5) {
            x -= 5;
            u += 5;
        }
        System.out.println(u);

        scan.close();
        return;
    }
}
/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