using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;

namespace Distance
{
    class Program
    {
        static void Main(string[] args)
        {
            double startSpeed = double.Parse(Console.ReadLine());
            double time1 = double.Parse(Console.ReadLine());
            double time2 = double.Parse(Console.ReadLine());
            double time3 = double.Parse(Console.ReadLine());

            double distanceOneHour = startSpeed * time1 / 60;//
            double distanceTenPercent = 10 * startSpeed / 100;
            double distance2Km = (distanceTenPercent + startSpeed) ;
            double d2 = time2 / 60;
            double distance2Hour = distance2Km * d2;//
            double distanceFivePercent = distance2Km - (5 * distance2Km / 100);
            double d3 = time3 / 60;
            double distanceFiveResult = distanceFivePercent * d3;//
            double result = distanceOneHour + distance2Hour + distanceFiveResult;

            Console.WriteLine("{0:f2}",result);
        }
    }
}