import java.util.*;
class Main
{
    public static void main(String[] args)
    {
        Scanner sc = new Scanner(System.in);
        
        long x = sc.nextInt();
        
        long power1000 = 0;
        long power5 = 0;
        
        power1000 = x/500;
        power5 = (x%500)/5;
        
        System.out.println(1000*power1000+5*power5);
    }
}
/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