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

namespace _3
{
    class Program
    {
        static void Main()
        {
            var youngBiker = double.Parse(Console.ReadLine());
            var oldBiker = double.Parse(Console.ReadLine());
            var typeTransport = Console.ReadLine();

            var total = 0.00;

            if (typeTransport == "trail")
            {
                    total += (youngBiker * 5.50 + oldBiker * 7) * 0.95;
            }
            else if (typeTransport == "cross-country")
            {
                if (youngBiker + oldBiker >= 50)
                {
                    total += (youngBiker*8 + oldBiker*9.50)*0.75*0.95;
                }
                else
                {
                    total += (youngBiker * 8 + oldBiker * 9.50) * 0.95;
                }

            }
            else if (typeTransport == "road")
            {
                total += (youngBiker * 20 + oldBiker * 21.50) * 0.95;
            }
            else if (typeTransport == "downhill")
            {
                total += (youngBiker * 12.25 + oldBiker * 13.75) * 0.95;

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

        }
    }
}