dictionary.com scraper

using HtmlAgilityPack;
using System;
using System.Collections.Generic;
using System.IO;
using System.Net;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        Regex r0 = new Regex("(?: |^)(\\p{Ll}+)(?:[ .,?!]|$)", RegexOptions.Compiled);
        IEnumerable<string> ieSsE0 = F0(r0);
        using (FileStream fs0 = File.Open("all_words.txt", FileMode.Create))
        using (StreamWriter sw0 = new StreamWriter(fs0))
        {
            foreach (string s0 in new SortedSet<string>(ieSsE0))
            {
                Console.WriteLine("Found {0}...", s0);
                sw0.WriteLine(s0);
            }
        }
        Console.WriteLine("Finished!");
    }

    static IEnumerable<string> F0(Regex r0)
    {
        Console.WriteLine("Scanning /list...");
        for (char c0 = 'a'; c0 <= 'z'; c0++)
            foreach (string s0 in F1(c0, r0))
                yield return s0;
        yield break;
    }

    static IEnumerable<string> F1(char c0, Regex r0)
    {
        Console.WriteLine("Scanning /list/{0}...", c0);
        for (int i0 = 1;; i0++)
        {
            IEnumerable<string> ieSsE0;
            try { ieSsE0 = F2(c0, i0, r0); }
            catch { yield break; }
            foreach (string s0 in ieSsE0)
                yield return s0;
        }
    }

    static IEnumerable<string> F2(char c0, int i0, Regex r0)
    {
        Console.WriteLine("Scanning /list/{0}/{1}...", c0, i0);
        HttpWebRequest hwr0 = WebRequest.CreateHttp("http://dictionary.reference.com/list/" + c0 + '/' + i0);
        hwr0.AllowAutoRedirect = false;
        using (HttpWebResponse hwr1 = (HttpWebResponse)hwr0.GetResponse())
        {
            if (hwr1.StatusCode == HttpStatusCode.MovedPermanently)
                throw new Exception();
            using (Stream s0 = hwr1.GetResponseStream())
            {
                HtmlDocument hd0 = new HtmlDocument();
                hd0.Load(s0);
                foreach (HtmlNode hn0 in hd0.DocumentNode.SelectNodes("/html/body/div[@class='content-container']/div[@class='words-list']/ul/li/span[@class='word']"))
                {
                    if (r0.IsMatch(hn0.InnerText))
                        yield return hn0.InnerText;
                    foreach (string s1 in F3(hn0.ParentNode.SelectSingleNode("span[@class='definition-link']/a").Attributes["href"].Value, r0))
                        yield return s1;
                }
            }
        }
        yield break;
    }

    static IEnumerable<string> F3(string s0, Regex r0)
    {
        Console.WriteLine("Scanning {0}...", new Uri(s0).AbsolutePath);
        using (WebResponse wr0 = WebRequest.Create(s0).GetResponse())
        using (Stream s1 = wr0.GetResponseStream())
        {
            HtmlDocument hd0 = new HtmlDocument();
            hd0.Load(s1);
            foreach (HtmlNode hn0 in hd0.DocumentNode.SelectNodes("//span"))
                foreach (Match m0 in r0.Matches(hn0.InnerText))
                    yield return m0.Captures[0].Value;
        }
        yield break;
    }
}