using System;

namespace SmallShop
{
    class Program
    {
        static void Main(string[] args)
        {
            string Drink = Console.ReadLine();
            string Town = Console.ReadLine();
            double Quantity = double.Parse(Console.ReadLine());

            double price = 0;

            if (Town == "Sofia" && Drink == "coffee")
            {
                price = Quantity * 0.50;
            }
            else if (Town == "Plovdiv" && Drink == "coffee")
            {
                price = Quantity * 0.40;
            }
            else if (Town == "Varna" && Drink == "coffee")
            {
                price = Quantity * 0.45; ;
            }
            else if (Town == "Sofia" && Drink == "water")
            {
                price = Quantity * 0.80;
            }
            else if (Town == "Plovdiv" || Town == "Varna" && Drink == "water")
            {
                price = Quantity * 0.70;
            }
            else if (Town == "Sofia" && Drink == "beer")
            {
                price = Quantity * 1.20;
            }
            else if (Town == "Plovdiv" && Drink == "beer")
            {
                price = Quantity * 1.15;
            }
            else if (Town == "Varna" && Drink == "beer")
            {
                price = Quantity * 1.10;
            }
            else if (Town == "Sofia" && Drink == "sweets")
            {
                price = Quantity * 1.45;
            }
            else if (Town == "Plovdiv" && Drink == "sweets")
            {
                price = Quantity * 1.30;
            }
            else if (Town == "Varna" && Drink == "sweets")
            {
                price = Quantity * 1.35;
            }
            else if (Town == "Sofia" && Drink == "peanuts")
            {
                price = Quantity * 1.60;
            }
            else if (Town == "Plovdiv" && Drink == "peanuts")
            {
                price = Quantity  * 1.50;
            }
            else if (Town == "Varna" && Drink == "peanuts")
            {
                price = Quantity * 1.55;
            }
            Console.WriteLine($"{price:F2}") ;
        }
    }
}