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)
        {
            var fruit = Console.ReadLine();
            var day = Console.ReadLine();
            var quantity = double.Parse(Console.ReadLine());
            var price = 0.0;


            if (day == "saturday" || day == "sunday")
            {
                if (fruit == "banana") { price = 2.70; }
                else if (fruit == "apple") { price = 1.25; }
                else if (fruit == "orange") { price = 0.90; }
                else if (fruit == "grapefruit") { price = 1.60; }
                else if (fruit == "kiwi") { price = 3.0; }
                else if (fruit == "pineapple") { price = 5.60; }
                else if (fruit == "grapes") { price = 4.20; }
            }
            else if (day == "monday" || day == "tuesday" || day ==
               "wednesday" || day == "thursday" || day == "friday")
            {
                if (fruit == "banana") { price = 2.50; }
                else if (fruit == "apple") { price = 1.20; }
                else if (fruit == "orange") { price = 0.85; }
                else if (fruit == "grapefruit") {price = 1.45;}
                else if (fruit == "kiwi") {price = 2.70;}
                else if (fruit == "pineapple") {price = 5.50;}
                else if (fruit == "grapes") {price = 3.85;}
            }
                if (price > 0)
                { Console.WriteLine("{0:f2}", price * quantity); }
                else { Console.WriteLine("error"); }

            }
        }
    }