using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""data"": [

                {

                  ""permalink_url"": ""https://www.facebook.com/347775946439542/photos/a.348021906414946/358023508748119/?type=3"",

                  ""id"": ""347775946439542_358023508748119""

                },

                {

                  ""permalink_url"": ""https://www.facebook.com/347775946439542/photos/a.348021906414946/350654269485043/?type=3"",

                  ""id"": ""347775946439542_350654269485043""

                },

                {

                  ""permalink_url"": ""https://www.facebook.com/347775946439542/photos/a.348021906414946/350651839485286/?type=3"",

                  ""id"": ""347775946439542_350651839485286""

                }

              ],

              ""paging"": {

                ""cursors"": {

                  ""before"": ""QVFIUlRGODNTaFZAueEUxQ2VvcHlrMUw1MGE0U0FCblhZAY1hVbFBGUHhHdXlrSkgzSm0tb05pSGpFOXBYVG9EcnN5T21sQTgtYy1jSjhrZAW9WYmg5YmpVMXpQWTRLUkQ3ZA05PcEZAjUTNyV2VuV05hRG8yVlBaa3pia3dFTVRLU05nU0pU"",

                  ""after"": ""QVFIUlBHMG44ZAkxHdUsxb012bVlOQ0ZAfaDhHLUZA6VEt6MHd0QjJYZADlfZAVk2aExSdlJESUU2SlVDaVJsYzI4dnlmUllZASzhKd3Nkb09aa2ZAMRHZAFTGhMVHFoQ1hjNE5zNDJ2aV96UGtVQUpBeHE1b2xUTzk2SHZALLTZA1Y3pZAZAmJOMENS""

                }

              }

            }";

        string permalinkUrl = (string)JObject.Parse(json).SelectToken("data[0].permalink_url");

        Console.WriteLine(permalinkUrl);

    }

​

}