using System;

public class Program

{

    public static void Main()

    {

        var product = Console.ReadLine().ToLower();

        var town = Console.ReadLine().ToLower();

        var quantity = double.Parse(Console.ReadLine());

        if (town == "sofia")

        {

            if (product == "cofee") Console.WriteLine(0.50 * quantity);

            if (product == "water") Console.WriteLine(0.80 * quantity);

            if (product == "beer") Console.WriteLine(1.20 * quantity);

            if (product == "sweets") Console.WriteLine(1.45 * quantity);

            if (product == "peanuts") Console.WriteLine(1.60 * quantity);

        }

        if (town == "plovdiv")

        {

            if (product == "cofee") Console.WriteLine(0.40 * quantity);

            if (product == "water") Console.WriteLine(0.70 * quantity);

            if (product == "beer") Console.WriteLine(1.15 * quantity);

            if (product == "sweets") Console.WriteLine(1.30 * quantity);

            if (product == "peanuts") Console.WriteLine(1.55 * quantity);

        }

        if (town == "varna")

        {

            if (product == "cofee") Console.WriteLine(0.45 * quantity);

            if (product == "water") Console.WriteLine(0.70 * quantity);

            if (product == "beer") Console.WriteLine(1.10 * quantity);

            if (product == "sweets") Console.WriteLine(1.35 * quantity);

            if (product == "peanuts") Console.WriteLine(1.55 * quantity);

        }

    }

}