using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
namespace _04.OnlineRadioDatabase
{
    class Program
    {
        static void Main(string[] args)
        {
            string fruit = Console.ReadLine();
            string day = Console.ReadLine();
            double quantity = double.Parse(Console.ReadLine());

            var price1 = new Dictionary<string, double>()
            {
                { "banana", 2.50 },
                { "apple", 1.20 },
                { "orange", 0.85 },
                { "grapefruit", 1.45 },
                { "kiwi", 2.70 },
                { "pineapple", 5.50 },
                { "grapes", 3.85 }
            };

            var price2 = new Dictionary<string, double>()
            {
                { "banana", 2.70 },
                { "apple", 1.25 },
                { "orange", 0.90 },
                { "grapefruit", 1.60 },
                { "kiwi", 3.00 },
                { "pineapple", 5.60 },
                { "grapes", 4.20 }
            };


            if (fruit == "banana" || fruit == "apple" || fruit == "orange" || fruit == "grapefruit" || fruit == "kiwi" || fruit == "pineapple" || fruit == "grapes")
            {
                double result1 = quantity * price1[fruit];
                double result2 = quantity * price2[fruit];
                if (day == "Monday" || day == "Tuesday" || day == "Wednesday" || day == "Thursday" || day == "Friday") Console.WriteLine("{0:0.00}", result1);

                else if (day == "Saturday" || day == "Sunday") Console.WriteLine("{0:0.00}", result2);

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