using System;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {

        var input = @"[{""unique_id"":55,""action_name"":""INSERT"",""start_date"":""2018-06-11T16:00:00"",""end_date"":""2018-06-11T17:00:00""},""1sddsd"",""my_channel""]";

        var output = JsonConvert.DeserializeObject<List<dynamic>>(input);

        Console.WriteLine(output[0].unique_id);

    }

}