using System;
using System.Collections.Generic;
using System.Text;

namespace FIshLand
{
    class Program
    {
        static void Main(string[] args)
        {
            double skumriqPrice = double.Parse(Console.ReadLine());
            double cacaPrice = double.Parse(Console.ReadLine());

            double amountPalamud = double.Parse(Console.ReadLine());
            double amountSafrid = double.Parse(Console.ReadLine());
            double kgMidi = double.Parse(Console.ReadLine());

            double PalamudPrice = skumriqPrice * 1.6;
            double safridPrice = cacaPrice * 1.8;
            double MidiPrice = 7.5;

            double palamudFinalPrice = amountPalamud * PalamudPrice;
            double safridFinalPrice = amountSafrid * safridPrice;
            double midiFinalPrice = kgMidi * MidiPrice;

            double totalPrice = palamudFinalPrice + safridFinalPrice + midiFinalPrice;

            Console.WriteLine($"{totalPrice:f2}");
        }
    }
}