using System;

namespace PlaceToWriteCode
{
    class Program
    {
        static void Main(string[] args)
        {
            string fruit = Console.ReadLine();
            string dayOfTheWeek = Console.ReadLine();
            double quantity = double.Parse(Console.ReadLine());
            double totalPrice = 0.0;



            if (dayOfTheWeek == "Monday" || dayOfTheWeek == "Tuesday" || dayOfTheWeek == "Wednesday" || dayOfTheWeek == "Thursday" || dayOfTheWeek == "Friday")
            {
                if (fruit == "banana")
                {
                    totalPrice = quantity * 2.5;
                }
                if (fruit == "apple")
                {
                    totalPrice = quantity * 1.2;
                }
                if (fruit == "orange")
                {
                    totalPrice = quantity * 0.85;
                }
                if (fruit == "grapefruit")
                {
                    totalPrice = quantity * 1.45;
                }
                if (fruit == "kiwi")
                {
                    totalPrice = quantity * 2.7;
                }
                if (fruit == "pineapple")
                {
                    totalPrice = quantity * 5.5;
                }
                if (fruit == "grapes")
                {
                    totalPrice = quantity * 3.85;
                }

                Console.WriteLine($"{totalPrice:f2}");

                else
                {
                    Console.WriteLine("error");
                }


            }







            else if (dayOfTheWeek == "Saturday" || dayOfTheWeek == "Sunday")
            {
                if (fruit == "banana")
                {
                    totalPrice = quantity * 2.7;
                }
                if (fruit == "apple")
                {
                    totalPrice = quantity * 1.25;
                }
                if (fruit == "orange")
                {
                    totalPrice = quantity * 0.9;
                }
                if (fruit == "grapefruit")
                {
                    totalPrice = quantity * 1.6;
                }
                if (fruit == "kiwi")
                {
                    totalPrice = quantity * 3;
                }
                if (fruit == "pineapple")
                {
                    totalPrice = quantity * 5.6;
                }
                if (fruit == "grapes")
                {
                    totalPrice = quantity * 4.2;
                }
                Console.WriteLine($"{totalPrice:f2}");

                else
                {
                    Console.WriteLine("error");
                }



            }

            else
            {
                Console.WriteLine("error");
            }

        }

    }
}