static void Main(string[] args)
        {
            Console.WriteLine("Hello world");

            var tbs = new Perc();

            tbs.d.init();

            var yem1 = new Yem();

            yem1.a = 777;

            var yem2 = new Yem();

            yem2.a = 666;

            tbs.d.Add(yem1);
            tbs.d.Add(yem2);

            Perc readin;

            DataContractSerializer ser = new DataContractSerializer(typeof(Perc));
            string output = JsonConvert.SerializeObject(tbs);

            using (FileStream fs = new FileStream(@".\a.xml", FileMode.Create)){
                XmlTextWriter writer = new XmlTextWriter(fs, Encoding.ASCII);
                writer.Formatting = System.Xml.Formatting.Indented;
                ser.WriteObject(writer, tbs);
                writer.Close();
            }

            using (FileStream fs = new FileStream(@".\a.xml", FileMode.Open))
            {
                XmlTextReader reader = new XmlTextReader(fs);
                readin = (Perc)ser.ReadObject(reader, true);
            }

            Console.ReadLine();
        }
        public int CompareTo(object obj)
        {
            Yem that = obj as Yem;

            return(this.a.CompareTo(that.a));
        }