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

namespace FruitShop
{
    class Program
    {
        static void Main(string[] args)
        {
            string fruits = Console.ReadLine();
            string dayOfWeek = Console.ReadLine().ToLower();
            double quantity = double.Parse(Console.ReadLine());
            double price = -1.0;

            if (dayOfWeek == "monday" || dayOfWeek == "tuesday" || dayOfWeek == "wednesday" || dayOfWeek == "thursday" ||
                dayOfWeek == "friday") ;
            {
                if (fruits == "banana") price = 2.50;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                }
            }
            if (fruits == "apple") price = 1.20;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
            }
            if (fruits == "orange") price = 0.85;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
            }
            if (fruits == "grapefruit") price = 1.45;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
            }
            if (fruits == "kiwi") price = 2.70;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
            }
            if (fruits == "pineapple") price = 5.50;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
            }
            if (fruits == "grapes") price = 3.85;
            {
                if (price >= 0)
                {
                    Console.WriteLine("{0:f2}", price * quantity);
                }
                else
                {
                    Console.WriteLine("error");
                }
                if (dayOfWeek == "saturday" || dayOfWeek == "sunday") ;
                {
                    if (fruits == "banana") price = 2.70;
                    {
                        if (price >= 0)
                        {
                            Console.WriteLine("{0:f2}", price * quantity);
                        }

                    }
                }
                if (fruits == "apple") price = 1.25;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }

                }
                if (fruits == "orange") price = 0.90;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                }
                if (fruits == "grapefruit") price = 1.60;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                }
                if (fruits == "kiwi") price = 3.00;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                }
                if (fruits == "pineapple") price = 5.60;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                }
                if (fruits == "grapes") price = 4.20;
                {
                    if (price >= 0)
                    {
                        Console.WriteLine("{0:f2}", price * quantity);
                    }
                    else
                    {
                        Console.WriteLine("error");
                    }
                }


            }
        }
    }
}