using System;

namespace Supplies_for_School
{
    class Program
    {
        static void Main(string[] args)
        {
            int pensQuantity = int.Parse(Console.ReadLine());
            int markersQuantity = int.Parse(Console.ReadLine());
            int preparQuantity = int.Parse(Console.ReadLine());
            int percentDiscount = int.Parse(Console.ReadLine());



            double pensPrice = pensQuantity * 5.80;
            double markersPrice = markersQuantity * 7.20;
            double preparPrice = preparQuantity * 1.20;
            double materialsPrice = pensPrice + markersPrice + preparPrice;
            double discount= percentDiscount / 100;

            double discountSum=   materialsPrice-discount;










            Console.WriteLine(discountSum);


        }
    }
}