import java.util.*;

public class Main{
  public static void main(String[] args) {
    Scanner sc=new Scanner(System.in);
    int x=sc.nextInt();
    int count1=0;
    int count2=0;

    while(x>=500){
      x-=500;
      count1++;
    }

    while(x>=5){
      x-=5;
      count2++;
    }

    System.out.println(count1*1000+count2*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