import java.util.*;

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

public class Main{
	public static void main(String[] arg){
    	Scanner sc=new Scanner(System.in);
      int x=sc.nextInt();
      long ans=0;
      ans+=1000*(long)((x)/500);
      ans+=5*(long)((x-500*(long)(x/500))/5);
      System.out.println(ans);
        
    }
}