import java.util.*;
 
public class Main {
	public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
    	int n = sc.nextInt();
        int coin500 = n / 500;
        int hapiness500 = coin500 * 1000;
        int coin5 = (n % 500) / 5;
        int hapiness5 = coin5 * 5;
        System.out.println(hapiness500 + hapiness5);
    }
}
/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