Distance

import java.util.Scanner;

public class Distance
{
    public static void main(String[] args)
    {
    Scanner scanner = new Scanner(System.in);


        int firstSpeed = Integer.parseInt(scanner.nextLine());
        int firstTime = Integer.parseInt(scanner.nextLine());
        int secondTime = Integer.parseInt(scanner.nextLine());
        int thirdTime = Integer.parseInt(scanner.nextLine());



        double firstDistans = firstSpeed * (firstTime / 60.0);
        double secondDistans = (firstSpeed * 1.10)*(secondTime/60.0);
        double thirdDistans = (firstSpeed * 1.1 * 0.95) * (thirdTime/60.0);
        double allDistans = firstDistans + secondDistans + thirdDistans;



        System.out.println(String.format("%.2f", allDistans));


    }
}