import java.util.Scanner;

public class BlagotvoritelnaKampaniq {
    public static void main(String[] args) {
        Scanner scan = new Scanner(System.in);
        int days = Integer.parseInt(scan.nextLine());
        int numOfBakers = Integer.parseInt(scan.nextLine());
        int numOfCakes = Integer.parseInt(scan.nextLine());
        int numOfWaffles = Integer.parseInt(scan.nextLine());
        int numOfPancakes = Integer.parseInt(scan.nextLine());
        double cakesPrice = numOfCakes * 45;
        double wafflesPrice = numOfWaffles * 5.80;
        double pancakesPrice = numOfPancakes * 3.20;
        double priceForOneDay = (cakesPrice + wafflesPrice + pancakesPrice) * numOfBakers;
        double priceForWholeCharity = priceForOneDay * days;
        double finalPrice = priceForWholeCharity - (priceForWholeCharity/8);
        System.out.printf("%.2f" , finalPrice);


    }
}