using System;
using System.Collections.Generic;

class Program
{
    static void Main(string[] args)
    {
        string fruit = Console.ReadLine();
        string day = Console.ReadLine();
        double quantity = double.Parse(Console.ReadLine());
        bool isValidDay = day == "Monday" || day == "Tuesday" ||
                          day == "Wednesday" || day == "Thursday" ||
                          day == "Friday" || day == "Saturday" ||
                          day == "Sunday";

        bool isWeekend = day == "Saturday" || day == "Sunday";
        var fruitPrices = new Dictionary<string, double>()
            {
                { "banana",isWeekend? 2.70:2.50 },
                { "apple",isWeekend? 1.25:1.20 },
                { "orange",isWeekend? 0.90:0.85 },
                { "grapefruit",isWeekend?1.60 :1.45 },
                { "kiwi", isWeekend?3.00:2.70 },
                { "pineapple",isWeekend? 5.60: 5.50},
                { "grapes",isWeekend?4.20: 3.85 }
            };

        if (isValidDay && fruitPrices.ContainsKey(fruit))
        {
            Console.WriteLine((fruitPrices[fruit] * quantity).ToString("F2"));
        }
        else
        {
            Console.WriteLine("error");
        }
    }
}