using System;
using System.Linq;
using System.Collections.Generic;
using System.Collections;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string product = Console.ReadLine();
            string city = Console.ReadLine();
            double quantity = double.Parse(Console.ReadLine());
            switch(city)
            {
                case "Sofia":
                    switch(product)
                    {
                        case "coffee":
                            Console.WriteLine(0.50 * quantity);
                            break;
                        case "water":
                            Console.WriteLine(0.80 * quantity);
                            break;
                        case "beer":
                            Console.WriteLine(1.20 * quantity);
                            break;
                        case "sweets":
                            Console.WriteLine(1.45 * quantity);
                            break;
                        case "peanuts":
                            Console.WriteLine(1.60 * quantity);
                            break;

                    }
                    break;
                case "Plovdiv":
                    switch (product)
                    {
                        case "coffee":
                            Console.WriteLine(0.40 * quantity);
                            break;
                        case "water":
                            Console.WriteLine(0.70 * quantity);
                            break;
                        case "beer":
                            Console.WriteLine(1.15 * quantity);
                            break;
                        case "sweets":
                            Console.WriteLine(1.30 * quantity);
                            break;
                        case "peanuts":
                            Console.WriteLine(1.50 * quantity);
                            break;

                    }
                    break;
                case "Varna":
                    switch (product)
                    {
                        case "coffee":
                            Console.WriteLine(0.45 * quantity);
                            break;
                        case "water":
                            Console.WriteLine(0.70 * quantity);
                            break;
                        case "beer":
                            Console.WriteLine(1.10 * quantity);
                            break;
                        case "sweets":
                            Console.WriteLine(1.35 * quantity);
                            break;
                        case "peanuts":
                            Console.WriteLine(1.55 * quantity);
                            break;

                    }
                    break;
                default:
                    Console.WriteLine("Error");
                    break;
            }

        }
    }
}