using System;

namespace магазин_за_плодове
{
    class Program
    {
        static void Main(string[] args)
        {
            var fruit = Console.ReadLine().ToLower();
            var weekDay = Console.ReadLine().ToLower();
            var quantity = double.Parse(Console.ReadLine());

            double itemPrice = 0;
            double price = 0;

            // DAYS OFF

            if (weekDay == "saturday" || weekDay == "sunday")
            {
                if (fruit == "banana")
                {
                    itemPrice = 2.70;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "apple")
                {
                    itemPrice = 1.25;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "orange")
                {
                    itemPrice = 0.90;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "grapefruit")
                {
                    itemPrice = 1.60;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "kiwi")
                {
                    itemPrice = 3.00;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "pineapple")
                {
                    itemPrice = 5.60;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "grapes")
                {
                    itemPrice = 4.20;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

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

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

            // WEEK DAYS

            if (weekDay == "monday" || weekDay == "tuesday" || weekDay == "wednesday" || weekDay == "thursday" || weekDay == "friday")
            {
                if (fruit == "banana")
                {
                    itemPrice = 2.50;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "apple")
                {
                    itemPrice = 1.20;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "orange")
                {
                    itemPrice = 0.85;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "grapefruit")
                {
                    itemPrice = 1.45;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "kiwi")
                {
                    itemPrice = 2.70;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "pineapple")
                {
                    itemPrice = 5.50;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

                else if (fruit == "grapes")
                {
                    itemPrice = 3.85;
                    price = itemPrice * quantity;
                    Console.WriteLine($"{price:F2}");
                }

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

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