import java.util.Scanner;

public class P07FruitMarket {
    public static void main(String[] args) {
        Scanner scanner = new Scanner(System.in);

        double priceStrawberries = Double.parseDouble(scanner.nextLine());
        double bananasKg = Double.parseDouble(scanner.nextLine());
        double orangesKg = Double.parseDouble(scanner.nextLine());
        double raspberriesKg = Double.parseDouble(scanner.nextLine());
        double strawberriesKg = Double.parseDouble(scanner.nextLine());

        double priceRaspberries = priceStrawberries * 0.50;
        double priceOranges = priceRaspberries - (priceRaspberries * 0.40);
        double priceBananas = priceRaspberries - (priceRaspberries * 0.80);

        double sumRaspberries = raspberriesKg * priceRaspberries;
        double sumOranges = orangesKg * priceOranges;
        double sumBananas = bananasKg * priceBananas;
        double sumStrawberries = strawberriesKg * priceStrawberries;

        double totalSum = sumStrawberries + sumRaspberries + sumBananas + sumOranges;

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