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

namespace ConsoleApp10
{
    class Program
    {
        static void Main(string[] args)
        {

            string product = Console.ReadLine().ToLower();
            string dayofweek = Console.ReadLine().ToLower();
            double quantity = double.Parse(Console.ReadLine());

            double price = -1.0;


            string saturday = "saturday";
            string sunday = "sunday";
            string friday = "friday";
            string thursday = "thursday";
            string wednesday = "wednesday";
            string tuesday = "tuesday";
            string monday = "monday";
            string banana = "banana";
            string apple = "apple";
            string orange = "orange";
            string grapefruit = "grapefruit";
            string kiwi = "kiwi";
            string pineapple = "pineapple";
            string grapes = "grapes";

            if (dayofweek == monday ||
                dayofweek == tuesday ||
                dayofweek == wednesday ||
                dayofweek == thursday ||
                dayofweek == friday)
            {
                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;
                }
            }
            else if (dayofweek == saturday ||
                     dayofweek == sunday)
            {
                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;
                }
            }
            double result = price * quantity;
            if (price < 0)
            {
                Console.WriteLine("error");
            }
            else { Console.WriteLine($"{result:f3}"); }
        }
    }
}