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

namespace ConsoleApplication1
{
    class Program
    {


        static void Main(string[] args)
        {
            string product = Console.ReadLine().ToLower();
            string city = Console.ReadLine().ToLower();
            double quantity = double.Parse(Console.ReadLine());
            switch (city)
            {
                case "sofia":
                    if (product == "coffee")
                    Console.WriteLine("{0:F2}", quantity * 0.50);


                    else if (product == "water")
                    Console.WriteLine("{0:F2}", quantity * 0.80);


                    if (product == "beer")
                    Console.WriteLine("{0:F2}", quantity * 1.20);


                    if (product == "sweets")
                    Console.WriteLine("{0:F2}", quantity * 1.45);


                    if (product == "peanuts")
                    Console.WriteLine("{0:F2}", quantity * 1.60);
                    break;


                case "plovdiv":
                    if (product == "coffee")
                    Console.WriteLine("{0:F2}", quantity * 0.40);

                    if (product == "water")
                    Console.WriteLine("{0:F2}", quantity * 0.70);

                    if (product == "beer")
                    Console.WriteLine("{0:F2}", quantity * 1.15);

                    if (product == "sweets")
                    Console.WriteLine("{0:F2}", quantity * 1.30);

                    if (product == "peanuts")
                    Console.WriteLine("{0:F2}", quantity * 1.50);
                    break;

                case "varna":
                    if (product == "coffee")
                    Console.WriteLine("{0:F2}", quantity * 0.45);

                    if (product == "water")
                    Console.WriteLine("{0:F2}", quantity * 0.70);

                    if (product == "beer")
                    Console.WriteLine("{0:F2}", quantity * 1.10);

                    if (product == "sweets")
                    Console.WriteLine("{0:F2}", quantity * 1.35);

                    if (product == "peanuts")
                    Console.WriteLine("{0:F2}", quantity * 1.55);
                    break;
            }
        }
    }

}