using System;

namespace VegetableMarket
{
    class Program
    {
        static void Main(string[] args)
        {
            var veggie = double.Parse(Console.ReadLine());
            var fruit = double.Parse(Console.ReadLine());
            var vegQ = int.Parse(Console.ReadLine());
            var fruQ = int.Parse(Console.ReadLine());

            double EUR = 1.94;

            double totalV = veggie * vegQ;
            double totalF = fruit * fruQ;

            Console.WriteLine("Total Earnings: " + ((totalV + totalF) / EUR));
        }
    }
}