namespace SquareOfStars
{
    using System;

    class Program
    {
        static void Main(string[] args)
        {
            string fruit = Console.ReadLine().ToLower();
            string dayOfTheWeek = Console.ReadLine().ToLower();
            double num = double.Parse(Console.ReadLine());
            double result = 0;
            double price=-1;
            if (dayOfTheWeek == "monday" ||
                dayOfTheWeek == "tuesday" ||
                dayOfTheWeek == "wednesday" ||
                dayOfTheWeek == "thursday" ||
                dayOfTheWeek == "friday")
            {
                if (fruit == "banana")
                {
                    price=2.5d;
                }
                else if (fruit == "apple")
                {
                    price=1.2d;
                }
                else if (fruit == "orange")
                {
                    price=0.85d;
                }
                else if (fruit == "grapefruit")
                {
                    price=1.45d;
                }
                else if (fruit == "kiwi")
                {
                    price=2.7d;
                }
                else if (fruit == "pineapple")
                {
                    price=5.5d;
                }
                else if (fruit == "grapes")
                {
                    price=3.85d;
                }
            }
            else if (dayOfTheWeek == "sunday" ||
                dayOfTheWeek == "saturday")
            {
                if (fruit == "banana")
                {
                    price=2.7d;
                }
                else if (fruit == "apple")
                {
                    price=1.25d;
                }
                else if (fruit == "orange")
                {
                    price=0.9d;
                }
                else if (fruit == "grapefruit")
                {
                    price=1.6d;
                }
                else if (fruit == "kiwi")
                {
                    price=3.0d;
                }
                else if (fruit == "pineapple")
                {
                    price=5.6d;
                }
                else if (fruit == "grapes")
                {
                    price=4.2d;

                }
            }

          if(price!=-1)
          {
            result=price*num;
            Console.WriteLine("{0:f2}", result);
          }
          else{
            Console.WriteLine("error");
          }
        }
    }
}