using System;

using System.Collections.Generic;

public class Program

{

    public class RankFromStream{

        private class TreeNode {

            public int Val;

            public int Rank;

            public TreeNode Left;

            public TreeNode Right;

            public TreeNode(int val, int rank){

                this.Val = val;

                this.Rank = rank;

            }

        }

        private TreeNode root;

        private Dictionary<int,int> valToRank;

        public RankFromStream(){

            valToRank = new Dictionary<int,int>();

        }

        private void Insert(TreeNode node, int x, int newRank){

            if (node.Val < x){

                //go right

                if (node.Right == null){

                    node.Right = new TreeNode(x, newRank+node.Rank+1);

                }

                else Insert(node.Right, x, newRank+node.Rank+1);

            }

            else {

                //go left

                node.Rank++;

                if (node.Left == null){

                    node.Left = new TreeNode(x, newRank);

                }

                else Insert(node.Left, x, newRank);

            }

        }

        public void Track(int x){

            if (root == null) {

                root = new TreeNode(x, 0);

                return;

            }

            Insert(root, x, 0);

        }

        private TreeNode Search(TreeNode node, int x){

            if (node == null) return null;

            if (node.Val == x) return node;

            if (node.Val < x){

                //go right

                return Search(node.Right, x);

            }

            else {

                //go left

                return Search(node.Left, x);

            }

        }

        public int GetRankOfNumber(int x){

            var node = Search(root, x);

            if (node == null) return -1;

            return node.Rank;

        }

    }

    public static void Main()

    {

        var RfS = new RankFromStream();

        RfS.Track(5);

        RfS.Track(1);

        RfS.Track(4);

        RfS.Track(4);

        RfS.Track(5);

        RfS.Track(9);

        RfS.Track(7);

        RfS.Track(13);

        RfS.Track(3);

        Console.WriteLine(RfS.GetRankOfNumber(1));

        Console.WriteLine(RfS.GetRankOfNumber(3));

        Console.WriteLine(RfS.GetRankOfNumber(4));

    }

}