using System;

namespace _06._Fishland
{
    class Program
    {
        static void Main(string[] args)
        {
            double cenaSkumriq = double.Parse(Console.ReadLine());
            double cenaCaca = double.Parse(Console.ReadLine());
            double kgPalamud = double.Parse(Console.ReadLine());
            double kgSafrid = double.Parse(Console.ReadLine());
            int kgMidi = int.Parse(Console.ReadLine());

            double cenaPalamud = cenaSkumriq + cenaSkumriq * 0.60;
            double sumaPalamud = kgPalamud * cenaPalamud;

            double cenaSafrid = cenaCaca + cenaCaca * 0.80;
            double sumaSafrid = kgSafrid * cenaSafrid;

            double sumaMidi = kgMidi * 7.50;

            double smetka = sumaPalamud + sumaMidi + sumaSafrid;

            Console.WriteLine(Math.Round(smetka,2));
        }
    }
}