using System; using System.Globalization;

namespace URI_Imposto_exer_1051 { class Program { static void Main(string[] args) { double value = double.Parse(Console.ReadLine(), CultureInfo.InvariantCulture); double acumula = 0; double value2 = 0; if (value >= 0 && value <= 2000) { Console.WriteLine("Isento"); }

        if (value > 2000 && value <= 3000)
        {
            value2 = value - 2000;
            acumula = value2 * 8 / 100;
        }
        if (value > 3000 && value <= 4500)
        {
            value2 = value - 3000;
            acumula = (1000 * 8 / 100);
            acumula += (value2 * 18 / 100);
        }
        if (value > 4500)
        {
            value2 = value - 4500;
            acumula = (1000 * 8 / 100);
            acumula += (1500 * 18 / 100);
            acumula += (value2 * 28 / 100);
        }
        Console.WriteLine("R$ " + acumula.ToString("F2", CultureInfo.InvariantCulture));

    }
}

}