using System;

public class Program

{

    public static void Main()

    {

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

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

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

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

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

        double raspberryPrice = strawberryPrice / 2;

        double total = strawberriesKg * strawberryPrice + bananasKg * raspberryPrice * 0.2 + orangesKg * raspberryPrice * 0.6 + raspberriesKg * raspberryPrice;

        Console.WriteLine($"{total}");

    }

}