using System;

public class Program

{

    public class TreeNode

    {

        public int Value {get; private set;}

        public TreeNode Left {get; private set;}

        public TreeNode Right {get; private set;}

        public TreeNode(int @value, TreeNode left = null, TreeNode right = null)

        {

            Value = @value;

            Left = left;

            Right = right;

        }

    }

    public static void InOrderTraversal(TreeNode root)

    {

        if(root == null)

        {

            return;

        }

        InOrderTraversal(root.Left);

        Console.WriteLine(root.Value);

        InOrderTraversal(root.Right);

    }

    static TreeNode previous = null;

    public static void InOrderSuccessor(TreeNode root, int target)

    {

        if(root == null)

        {

            return;

        }

        InOrderSuccessor(root.Left, target);

        if(previous != null && previous.Value == target)

        {

            Console.WriteLine(root.Value);

        }

        previous = root;

        InOrderSuccessor(root.Right, target);

    }

    public static void Main()

    {

        TreeNode root = new TreeNode(10, new TreeNode(7, new TreeNode(5), new TreeNode(9)), new TreeNode(35, new TreeNode(30), new TreeNode(45)));

        //InOrderTraversal(root);

        InOrderSuccessor(root, 10);

    }

}