using System;

using Newtonsoft.Json.Linq;

public class Program

{

    public static void Main()

    {

        string json = @"

            {

              ""client_id"": ""26075235"",

              ""client_version"": ""1.0.0"",

              ""event"": ""app.uninstall"",

              ""timestamp"": 1478741247,

              ""data"": {

                ""user_id"": ""62581379"",

                ""site_id"": ""837771289247593785"",

                ""platform_app_id"": ""26075235""

              }

            }";

        JObject jo = JObject.Parse(json);

        Console.WriteLine("User ID: " + (string)jo.SelectToken("data.user_id"));

    }

}