Simple Facebook video download

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Web;
using System.Net;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using System.Text.RegularExpressions;

namespace DecodingEntities
{
    class Program
    {
        public static WebClient wc = new WebClient();
        static void Main(string[] args)
        {
    //JSON.net library required to run this code. http://james.newtonking.com/json
            //url = "https://www.facebook.com/video.php?v=1452983714984650";
            Console.WriteLine("Insert video URL:");
            string url = Console.ReadLine();
            string strRegex = @"params\"",\""(.*)\""]";
            Regex myRegex = new Regex(strRegex, RegexOptions.None);

            wc.Headers.Add("User-Agent", "Mozilla/5.0 (Windows NT 5.1; rv:31.0) Gecko/20100101 Firefox/31.0");
            wc.Headers.Add("Content-Type", "text/html; charset=utf-8");
            string html = "";
            bool error = false;
            try
            {
                html = wc.DownloadString(url);
            }
            catch (WebException wex)
            {
                Console.WriteLine("Invalid URL");
                error = true;
            }

            if (!error)
            {
                string title = Regex.Match(html, @"<title id=\""pageTitle\"">(.*?) | .*? </title>").Groups[1].Value;
                string para = myRegex.Match(html).Groups[1].Value;

                para = clearEntities(para);

                int lindex = 0;
                string[] s = para.Split('}');
                for (int i = 0; i < 2; i++)
                {
                    lindex += s[i].Length;
                }
                para = para.Substring(0, lindex + 2);

                Console.WriteLine("Searching video link...");
                try
                {
                    List<Dictionary<string, string>> video_data = JObject.Parse(para).SelectToken("video_data").ToObject<List<Dictionary<string, string>>>();

                    if (video_data[0].ContainsKey("hd_src"))
                    {
                        Console.WriteLine("Downloading HD video.\r\nStoring video: "+title+".mp4");
                        DescarregaVideo(video_data[0]["hd_src"], title);
                    }
                    else if (video_data[0].ContainsKey("sd_src"))
                    {
                        Console.WriteLine("Downloading SD video.\r\nStoring video: " + title + ".mp4");
                        DescarregaVideo(video_data[0]["sd_src"], title);
                    }
                    else
                    {
                        Console.WriteLine("No link.");
                    }
                }
                catch (Exception ex)
                {
                    Console.WriteLine("Error searching link.");
                }
            }

            Console.ReadKey();
        }

        public static void DescarregaVideo(string url, string nom)
        {
            try
            {
                wc.DownloadFile(url, nom + ".mp4");
                Console.WriteLine("Download Complete.");
            }
            catch (WebException wex)
            {
                Console.WriteLine("Error during video download.");
            }
        }

        public static string clearEntities(string para)
        {
            para = para.Replace("[", "");
            para = para.Replace("]", "");

            para = para.Replace("\\u00257B", "{");
            para = para.Replace("\\u00257D", "}");
            para = para.Replace("\\u002522", "\"");
            para = para.Replace("\\u00253A", ":");
            para = para.Replace("\\u00252C", ",");


            para = para.Replace("\\u00255C", "\\");
            para = para.Replace("\\u00252F", "/");
            para = para.Replace("\\u00253F", "?");
            para = para.Replace("\\u00253D", "=");
            para = para.Replace("\\u002526", "&");

            para = para.Replace("\\u00255B", "[");
            para = para.Replace("\\u00255D", "]");

            return Uri.UnescapeDataString(para)+"\"}";
        }
    }
}