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

namespace Distance
{
    class Distance
    {
        static void Main(string[] args)
        {
            var a = double.Parse(Console.ReadLine());
            var b = float.Parse(Console.ReadLine());
            var c = float.Parse(Console.ReadLine());
            var d = float.Parse(Console.ReadLine());


            var pyrvo = a * (b / 60);
            var vtoro = (a + (a * 0.1)) * (c / 60);
            var treto = ((a + (a * 0.1)) - a * 0.05) * (d / 60);
           var l = pyrvo + vtoro + treto;
            Console.WriteLine("{0:f2}", l);


        }
    }
}