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

namespace _07.Fruit_Shop
{
    class Program
    {
        static void Main(string[] args)
        {
            string product = Console.ReadLine();
            var dayOfWeek = Console.ReadLine();
            double quantity = double.Parse(Console.ReadLine());
            double price = 0.0;

            bool dayOfWeek1 = (dayOfWeek == "Monday" || dayOfWeek == "Thursday" || dayOfWeek == "Tuesday"
                                                     || dayOfWeek == "Wednesday" || dayOfWeek == "Friday");

            bool dayOfWeek2 = dayOfWeek == "Saturday" || dayOfWeek == "Sunday";

            if (dayOfWeek1 == true)
            {
                if (product == "banana")
                {
                    price = 2.50;
                }
                else if (product == "apple")
                {
                    price = 1.20;
                }
                else if (product == "orange")
                {
                    price = 0.85;
                }
                else if (product == "grapefruit")
                {
                    price = 1.45;
                }
                else if (product == "kiwi")
                {
                    price = 2.70;
                }
                else if (product == "pineapple")
                {
                    price = 5.50;
                }
                else if (product == "grapes")
                {
                    price = 3.85;
                }
            }
            /////////////////////////////////////

            if (dayOfWeek2 == true)
            {
                if (product == "banana")
                {
                    price = 2.70;
                }
                else if (product == "apple")
                {
                    price = 1.25;
                }
                else if (product == "orange")
                {
                    price = 0.90;
                }
                else if (product == "grapefruit")
                {
                    price = 1.60;
                }
                else if (product == "kiwi")
                {
                    price = 3.00;
                }
                else if (product == "pineapple")
                {
                    price = 5.60;
                }
                else if (product == "grapes")
                {
                    price = 4.20;
                }
            }

            else if (dayOfWeek1 == false)
            {
                Console.WriteLine("error");
            }
            else if (dayOfWeek2 == false)
            {
                Console.WriteLine("error");
            }
            else if (price < 0)
            {
                Console.WriteLine("error");
            }
            Console.WriteLine("{0:F2}", quantity * price);
        }
    }
}