import java.util.*;


public class Main {
    public static void main(String[] args) throws Exception {
        Scanner sc = new Scanner(System.in);
        
        int x = sc.nextInt();
        int ans=0;
        
        for(int i=0; x>499; i++){
            x=x-500;
            ans+=1000;
        }
        
        for(int i=0; x>4; i++){
            x=x-5;
            ans+=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