using System;

​

public class Program

{

    public static void Main()

    {

        var city = Console.ReadLine();

        var prod = Console.ReadLine();

        var q = int.Parse(Console.ReadLine());

        if(prod == "coffee"){

            if(city == "Sofia") Console.Write(0.50*q);

            else if(city == "Plovdiv") Console.Write(0.40*q);

            else Console.Write(0.45*q);

        } else if(prod == "water"){

            if(city == "Sofia") Console.Write(0.80*q);

            else if(city == "Plovdiv") Console.Write(0.70*q);

            else Console.Write(0.70*q);

        } 

         else if(prod == "beer"){

            if(city == "Sofia") Console.Write(1.20*q);

            else if(city == "Plovdiv") Console.Write(1.15*q);

            else Console.Write(1.10*q);

        } 

         else if(prod == "sweets"){

            if(city == "Sofia") Console.Write(1.45*q);

            else if(city == "Plovdiv") Console.Write(1.30*q);

            else Console.Write(1.35*q);

        } else {

         if(city == "Sofia") Console.Write(1.60*q);

            else if(city == "Plovdiv") Console.Write(1.50*q);

            else Console.Write(1.55*q);

         }

    }

}