static void Main(string[] args)
        {
            btree        tree1 = new btree(2), tree2 = new btree(2);
            StreamReader reader = new StreamReader("input.dat");
            string       str    = reader.ReadLine();

            string[] mass = str.Split(new Char[] { ' ' });
            foreach (string i in mass)
            {
                tree1.Insert(Convert.ToInt32(i));
            }
            str  = reader.ReadLine();
            mass = str.Split(new Char[] { ' ' });
            foreach (string i in mass)
            {
                tree2.Insert(Convert.ToInt32(i));
            }
            Console.WriteLine("Превое дерево:");
            output(tree1.root);
            Console.WriteLine("Второе дерево:");
            output(tree2.root);
            recursion(tree1, tree2.root);
            Console.WriteLine("Результат:");
            output(tree1.root);
            Console.Read();
        }
 static void recursion(btree treebase, btree.node treedel)
 {
     foreach (int i in treedel.keys)
     {
         treebase.Delete(i);
     }
     foreach (btree.node i in treedel.childs)
     {
         recursion(treebase, i);
     }
 }