using System;

    namespace Fruit_Shop
    {
        class Program
        {
            static void Main(string[] args)
            {
                string fruit = Console.ReadLine();
                string DayOfWeek = Console.ReadLine();
                double quantity = double.Parse(Console.ReadLine());

                double price = 0;


                switch (fruit)
                {
                    case "banana":
                        if(DayOfWeek=="Monday"||DayOfWeek== "Tuesday"||DayOfWeek== "Wednesday"||DayOfWeek== "Thursday"||DayOfWeek== "Friday ")
                        {
                            price = 2.50;
                        }
                        else if(DayOfWeek== "Saturday"||DayOfWeek== "Sunday")
                        {
                            price = 2.70;
                        }
                        break;
                    case "apple":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 1.20;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 1.25;
                        }
                        break;
                    case "orange":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 0.85;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 0.90;
                        }
                        break;
                    case "grapefruit":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 1.45;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 1.60;
                        }
                        break;
                    case "kiwi":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 2.70;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 3.00;
                        }
                        break;
                    case "pineapple":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 5.50;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 5.60;
                        }
                        break;
                    case "grapes":
                        if (DayOfWeek == "Monday" || DayOfWeek == "Tuesday" || DayOfWeek == "Wednesday" || DayOfWeek == "Thursday" || DayOfWeek == "Friday ")
                        {
                            price = 3.85;
                        }
                        else if (DayOfWeek == "Saturday" || DayOfWeek == "Sunday")
                        {
                            price = 4.20;
                        }
                        break;

                }
            if (price * quantity == 0.00)
            {
                Console.WriteLine("error");
            }
            else
            {
                Console.WriteLine($"{price * quantity:f2}");
            }


            }
        }
    }