Read data from JSON properties having @ prefix using C# .Net

hello sir,

I want to know how to retrieve data in json format with "@" prefix, below is the json I retrieved

{"@averageBaseRate":"574.27","@averageRate":"430.7","@commissionableUsdTotal":"430.7","@currencyCode":"USD","@maxNightlyRate":"430.7","@nightlyRateTotal":"430.7","@surchargeTotal":"76.23","@total":"506.93"

this is the way i retrieve value but I get null value .Element without @ prefix are retrieved properly 

foreach (var a in root.HotelRoomAvailabilityResponse.HotelRoomResponse)
                    {
 string average = a.RateInfos.RateInfo.ChargeableRateInfo.@averageRate;
}

below is my class that I used

public class RootObject
        {
            public HotelRoomAvailabilityResponse HotelRoomAvailabilityResponse { get; set; }
        }
public class HotelRoomAvailabilityResponse
        {
 public dynamic HotelRoomResponse { get; set; }
}

 public class HotelRoomResponse
        {
 public RoomImages RoomImages { get; set; }
}

 public class RateInfos
        {
            public string @size { get; set; }
            public RateInfo RateInfo { get; set; }
        }
 public class RateInfo
        {
            public ChargeableRateInfo ChargeableRateInfo { get; set; }
          }

  public class ChargeableRateInfo
        {
            public string @averageRate { get; set; }
}