static void Main(string[] args)
        {
            Console.WriteLine("---- Xml Interface ----");
            ISystem xmlSystem = SystemFactory.GetSystemXML();

            Execute(xmlSystem, "xml_input.txt");
            Console.WriteLine();

            Console.WriteLine("---- KeyValue Interface ----");
            Console.WriteLine("---- Xml Interface ----");
            ISystem keyValueSystem = SystemFactory.GetSystemKeyValue();

            Execute(keyValueSystem, "key_value_input.txt");
            Console.WriteLine();
        }