mobile operator

using System;

namespace exampreparation
{
    class exam
    {
        static void Main(string[] args)
        {
            string duration = Console.ReadLine();
            string contract = Console.ReadLine();
            string mobileNet = Console.ReadLine();
            int months = int.Parse(Console.ReadLine());
            double price = 0.0;

            if (duration == "one")
            {
                if (contract == "Small")
                {
                    price = 9.98;
                }
                else if (contract == "Middle")
                {
                    price = 18.99;
                }
                else if (contract == "Large")
                {
                    price = 25.98;
                }
                else
                {
                    price = 35.99;
                }
            }
            else
            {
                if (contract == "Small")
                {
                    price = 8.58;
                }
                else if (contract == "Middle")
                {
                    price = 17.09;
                }
                else if (contract == "Large")
                {
                    price = 23.59;
                }
                else
                {
                    price = 31.79;
                }

            }

            if (mobileNet == "yes")
            {
                if (price <= 10)
                {
                    price += 5.50;
                }
                else if (price <= 30)
                {
                    price += 4.35;
                }
                else
                {
                    price += 3.85;
                }
            }

            double bill = price * months;

            if (duration == "two")
            {
                bill *= 0.9625;
            }

            Console.WriteLine($"{bill:f2} lv.");
        }
    }
}