parsowanie html c#

using System;
using System.Collections.Generic;
using System.ComponentModel;
using System.Data;
using System.Drawing;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;
using System.Net;
using System.IO;
using System.Threading.Tasks;
using System.Windows.Forms;
using HtmlAgilityPack;

 label1.Text = "1 USD";
                List<string> kursy = new List<string>();

                WebClient web = new WebClient();
                string html = web.DownloadString("http://kursy-walut.mybank.pl/");
                MatchCollection m1 = Regex.Matches(html, @"<td id=\"GBPPLN_NBP\">\\s*(.+?)\\s*</td>", RegexOptions.Singleline);
                foreach (Match m in m1)
                {
                    if (m.Groups[1].Value != "")
                        {
                        string kurs = m.Groups[1].Value;
                        kursy.Add(kurs);
                    }
                }
                listBox1.DataSource = kursy;

 MatchCollection m1 = Regex.Matches(html, @"<td id=\"GBPPLN_NBP\">\\s*(.+?)\\s*</td>", RegexOptions.Singleline);

     var html = @"http://kursy-walut.mybank.pl/";

     HtmlWeb web = new HtmlWeb();
     var htmlDoc = web.Load(html);

     string tresc = htmlDoc.DocumentNode.SelectSingleNode(" /*tutaj wklejasz co skopiowales z chrome */").InnerText;

htmlDoc.DocumentNode.SelectSingleNode("//*[@id="article"]/table/tbody/tr/td/center/table[1]/tbody/tr[2]/td[3]").InnerText;

 string tresc = htmlDoc.DocumentNode.SelectSingleNode("//*[@id=\"GBPPLN_NBP\"]").InnerText;