import java.util.*;
class Main{
    static Scanner sc=new Scanner(System.in);
    public static void main(String[] args){
        long X = sc.nextLong();
        long n500 = X/500;
        long n5 = (X%500)/5;
        System.out.println(n500*1000+n5*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