using System;
namespace trade_commisions
{
    class Program
    {
        static void Main(string[] args)
        {
            var town = Console.ReadLine().ToLower();
            var sales = double.Parse(Console.ReadLine());
            var commissions = -1.0;

      	    if (sales <0){
         	 Console.WriteLine("error");
         	 return;}
			if (town != "sofia" && town != "varna" && town !="plovdiv"){
			Console.WriteLine("error");
			}


            if (town == "sofia")
            {
                if (0 <= sales && sales <= 500) commissions = 0.05;
                else if (500 <= sales && sales <= 1000) commissions = 0.07;
                else if (1000 <= sales && sales <= 10000) commissions = 0.08;
                else if (sales >= 10000) commissions = 0.12;
            }
             if (town == "varna")
            {
                   if (0 <= sales && sales <= 500) commissions = 0.045;
                else if (500 <= sales && sales <= 1000) commissions = 0.075;
                else if (1000 <= sales && sales <= 10000) commissions = 0.10;
                else if (sales >= 10000) commissions = 0.13;
            }
             if (town == "plovdiv")
            {
                 if (0 <= sales && sales <= 500) commissions = 0.055;
                else if (500 <= sales && sales <= 1000) commissions = 0.08;
                else if (1000 <= sales && sales <= 10000) commissions = 0.12;
                else if (sales >= 10000) commissions = 0.145;
            }
            if (commissions >= -1.0)
            {
                Console.WriteLine("{0:f2}", (commissions * sales));
            }
            else

                Console.WriteLine("Error");

        }
    }
}