using System;

public class Program

{

    public static void Main()

    {

        var Fruit = Console.ReadLine().ToLower();

        var Day = Console.ReadLine().ToLower();

        var quantity = double.Parse(Console.ReadLine());

        var price = -1.0;

        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;

        }

        else 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 = 3.00;

            else if(Fruit=="pineapple") price = 5.60;

            else if(Fruit=="grapes") price = 4.20;

        }

        if(price >=0) Console.WriteLine("{0:f2}",price*quantity);

        else Console.WriteLine("error");

    }

}