import java.net.SocketOption;
import java.util.Scanner;

import static java.lang.Math.PI;

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

        int days = Integer.parseInt(scanner.nextLine());
        int bakers = Integer.parseInt(scanner.nextLine());
        int cakes = Integer.parseInt(scanner.nextLine());
        int goffrets = Integer.parseInt(scanner.nextLine());
        int pancakes = Integer.parseInt(scanner.nextLine());



        double cakePrice = 45;
        double goffretsPrice = 5.80;
        double pancakePrice = 3.20;

        double sumPerDay = ((cakes * cakePrice) + (goffrets * goffretsPrice) + (pancakes * pancakePrice));
        double totalSum = sumPerDay * days;
        double finalSum = totalSum * 0.875;

        System.out.printf("%.2f", finalSum);



    }
}