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

namespace ConsoleApp1
{
    class Program
    {
        static void Main(string[] args)
        {
            var d = int.Parse(Console.ReadLine());
            var s = int.Parse(Console.ReadLine());
            var h = int.Parse(Console.ReadLine());
            var pr = double.Parse(Console.ReadLine());
            var VAqua = d * s * h;
            var VWater = VAqua * 0.001;
            var procent = pr * 0.01;
            var result = VWater * (1 - procent);


                Console.WriteLine("{0:f3}", result);


        }
    }
}