import java.util.*;
public class Main {
	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int x = in.nextInt();
		int total =0;
		int fivehund = x/500;
		total = fivehund * 1000;
		int a = x - (fivehund * 500);
		int fives = a / 5;
		total+= fives*5;
		System.out.println(total);
	}
	
}
/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