using System;


class Program
{
    static void Main(string[] args)
    {
        int initSpeed = int.Parse(Console.ReadLine());
        int firstPeriod = int.Parse(Console.ReadLine());
        int secondPeriod = int.Parse(Console.ReadLine());
        int thirdPeriod = int.Parse(Console.ReadLine());
        double initDistance = initSpeed * (firstPeriod / 60.0);
        double startSpeed = (initSpeed + initSpeed * 0.1);
        double incrDistance = startSpeed * (secondPeriod / 60.0);
        double endSpeed = startSpeed - startSpeed * 0.05;
        double decrDistance = endSpeed * (thirdPeriod / 60.0);
        Console.WriteLine((initDistance + incrDistance + decrDistance).ToString("F"));
    }
}