import java.util.*;

public class Main {
	public static void main(String[] args) {
		Scanner input = new Scanner(System.in);
		int X = input.nextInt();
		int ure500=0;
		int ure5=0;
		int j=0;
		int k=0;
		
		j=X/500;
		X-=500*j;
		
		k=X/5;
		
		ure500=j*1000;
		ure5=k*5;
		
		System.out.println(ure500+ure5);
		
	}
}

/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