import java.util.*;

public class Main{

	public static void main(String[] args){

		Scanner sc = new Scanner(System.in);
        int X = sc.nextInt();
      
        int most = X / 500;
        int least = (X-most*500)/5;
      
        int ans = most*1000 + least*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