using System;

public class TreeNode<T>

{

    public T Key{get; set;}

    public TreeNode<T> Left{get; set;}

    public TreeNode<T> Right{get; set;}

​

    public TreeNode(T key)

    {

        this.Key = key;

    }

    public static implicit operator TreeNode<T>((TreeNode<T>, T, TreeNode<T>) t) => new TreeNode<T>(t.Item2) {Left = t.Item1,  Right=t.Item3};

    public static implicit operator TreeNode<T>((T, T, TreeNode<T>) t) => new TreeNode<T>(t.Item2) {Left = new TreeNode<T>(t.Item1),  Right=t.Item3};

    public static implicit operator TreeNode<T>((TreeNode<T>, T, T) t) => new TreeNode<T>(t.Item2) {Left = t.Item1,  Right=new TreeNode<T>(t.Item3)};

    public static implicit operator TreeNode<T>((T, T, T) t) => new TreeNode<T>(t.Item2) {Left = new TreeNode<T>(t.Item1),  Right=new TreeNode<T>(t.Item3)};

}

​

public class Program

{

    public static void Main()

    {

        TreeNode<int> tree = ( ( 1, 3, null), 2, ( ( null, 3, 4 ), 5, ( 6, 7, 8 ) ) );

        Console.WriteLine(tree.Left.Key);

    }

}