using System;

using System.Linq;

using System.Net;

using System.Collections.Generic;

using Newtonsoft.Json;

public class Program

{

    public static void Main()

    {       

        var url = "https://bittrex.com/api/v1.1/public/getmarketsummary?market=usdt-btc";

        var json = new WebClient().DownloadString(url);

        var root = JsonConvert.DeserializeObject<RootObject>(json);

        Console.WriteLine(root.Result.Last().TimeStamp);

    }

    public class Result

    {

        public string MarketName { get; set; }

        public double High { get; set; }

        public double Low { get; set; }

        public double Volume { get; set; }

        public double Last { get; set; }

        public double BaseVolume { get; set; }

        public DateTime TimeStamp { get; set; }

        public double Bid { get; set; }

        public double Ask { get; set; }

        public int OpenBuyOrders { get; set; }

        public int OpenSellOrders { get; set; }

        public double PrevDay { get; set; }

        public DateTime Created { get; set; }

    }

​

    public class RootObject

    {

        public bool Success { get; set; }

        public string Message { get; set; }

        public List<Result> Result { get; set; }

    }

}