using System;
using System.Collections.Generic;
using System.Linq;

namespace ConsoleApp4
{
    class Program
    {
        static void Main(string[] args)
        {
            var fruit = Console.ReadLine();
            var dayOfWeek = Console.ReadLine();
            var calculation = double.Parse(Console.ReadLine());

            string[] workdaysDays = { "Monday", "Tuesday", "Wednesday", "Thursday", "Friday" };
            string[] weekendDays = { "Saturday", "Sunday" };

            Dictionary<string, double> workdays = new Dictionary<string, double>();
            workdays.Add("banana", 2.50);
            workdays.Add("apple", 1.20);
            workdays.Add("orange", 0.85);
            workdays.Add("grapefruit", 1.45);
            workdays.Add("kiwi", 2.70);
            workdays.Add("pineapple", 5.50);
            workdays.Add("grapes", 3.85);
            Dictionary<string, double> weekend = new Dictionary<string, double>();
            weekend.Add("banana", 2.70);
            weekend.Add("apple", 1.25);
            weekend.Add("orange", 0.90);
            weekend.Add("grapefruit", 1.60);
            weekend.Add("kiwi", 3.00);
            weekend.Add("pineapple", 5.60);
            weekend.Add("grapes", 4.20);

            if (workdaysDays.Any(dayOfWeek.Contains))
            {
                try
                {
                    var price = workdays[fruit];
                    Console.WriteLine($"{price*calculation:f2}");
                }
                catch (Exception)
                {
                    Console.WriteLine("error");
                }
            }
            else if(weekendDays.Any(dayOfWeek.Contains))
            {
                try
                {
                    var price = weekend[fruit];
                    Console.WriteLine($"{price * calculation:f2}");
                }
                catch (Exception)
                {
                    Console.WriteLine("error");
                }
            }
            else
            {
                Console.WriteLine("error");
            }
        }
    }
}