using System;

public class Program

{

    public static void Main()

    {

        double priceWhiskey = double.Parse(Console.ReadLine());

        double amountBeer = double.Parse(Console.ReadLine());

        double amountWine = double.Parse(Console.ReadLine());

        double amountRakia = double.Parse(Console.ReadLine());

        double amountWhiskey = double.Parse(Console.ReadLine());

        double priceRakia = priceWhiskey / 2;

        double priceWine = priceRakia - (priceRakia * 0.4);

        double priceBeer = priceRakia - (priceRakia * 0.8);

        double sumRakia = amountRakia * priceRakia;

        double sumWine = amountWine * priceWine;

        double sumBeer = amountBeer * priceBeer;

        double sumWhiskey = amountWhiskey * priceWhiskey;

        double sumFinal = sumRakia + sumWine + sumBeer + sumWhiskey;

        Console.WriteLine("{0:F2}", sumFinal);

    }

}