import java.util.*;
public class Main {
	//定義関数から参照できる変数定義はこの辺
	public static void main(String[] args) {
    	Scanner sc = new Scanner(System.in);
		int X =sc.nextInt();
		long sum = 0;
		long remain_1 = 0;
		long quo_1 = 0;
		//long remain_2 = 0;
		long quo_2 = 0;

		quo_1=X/500;
		remain_1 = X%500;
		quo_2=remain_1/5;
		sum=(quo_1*1000)+(quo_2*5);

		System.out.println(sum);
		//System.out.print(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