using System;

​

public class Program

{

    public static void Main()

    {

        int n1 = Convert.ToInt32(Console.ReadLine());

        int n2 = Convert.ToInt32(Console.ReadLine());

        string trace = Console.ReadLine();

        double priceJ, priceS;

        double sum = 0;

        double razhodi=0;

        if(trace=="cross-country" && n1+n2>=50)

        {

            priceJ = 8-8*0.25;

            priceS = 9.5-9.5*0.25;

            sum = n1 * priceJ + n2 * priceS;

            razhodi=5*sum/100.0;

        }

        else if (trace == "cross-country")

        {

            priceJ=8;

            priceS=9.5;

            sum = n1 * priceJ + n2 * priceS;

            razhodi=5*sum/100.0;

        }

​

        if (trace == "trail")

        {

            priceJ = 5.5;

            priceS = 7;

            sum = n1*priceJ + n2*priceS;

            razhodi=5*sum/100.0;

        }

​

        if (trace == "downhill")

        {

            priceJ = 12.25;

            priceS = 13.75;

            sum = n1 * priceJ + n2 * priceS;

            razhodi=5*sum/100.0;

        }

​

        if (trace == "road")

        {

            priceJ = 20;

            priceS = 21.5;

            sum = n1 * priceJ + n2 * priceS;

            razhodi=5*sum/100.0;

        }

​

        Console.WriteLine("{0:0.00}", sum-razhodi);

    }

}