import java.util.Scanner;

public class alcohol {
    public static void main(String[] args) {
        Scanner piqn = new Scanner(System.in);
        double priceWhiskey = Double.parseDouble(piqn.nextLine());
        double volumeBeer = Double.parseDouble(piqn.nextLine());
        double volumeWine = Double.parseDouble(piqn.nextLine());
        double volumeVodka = Double.parseDouble(piqn.nextLine());
        double volumeWhiskey = Double.parseDouble(piqn.nextLine());
        double priceVodka = priceWhiskey/2;
        double priceWine = priceVodka*0.6;
        double priceBeer = priceVodka*0.2;
        double totalPrice = volumeBeer*priceBeer + volumeVodka*priceVodka + volumeWhiskey*priceWhiskey + volumeWine*priceWine;
        System.out.printf("%.2f", totalPrice);


    }
}