import java.io.*;
import java.util.*;
public class Main
{
	public static void main(String[] args)throws IOException {
		InputStreamReader read=new InputStreamReader(System.in);
		BufferedReader in=new BufferedReader(read);
		int x=Integer.parseInt(in.readLine());
		long ans=0;
		while(x>=500)
		{
		    ans+=1000;
		    x-=500;
		}
		while(x>=5)
		{
		    ans+=5;
		    x-=5;
		}
		System.out.println(ans);
	}
}

/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