import java.util.*;

public class Main{
  public static void main(String[] args) {
		Scanner sc = new Scanner(System.in);
		int X = sc.nextInt();
		int Five_Count = 0;
		int Thousand_Count = 0;
		int num = 0;
		for(int i = 0;i < X;i++) {
			num = X % 500;
			Thousand_Count = X / 500;
			Five_Count = num / 5;
		}
		System.out.println(Thousand_Count * 1000 + Five_Count * 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