CS1001 Identifier expected

void Main()
{
	var port = new Port();
	Console.ReadLine();
}

public class Port
{
	Stopwatch Stopwatch { get; set; }
	SerialPort SerialPort { get; set; }

	public Port()
	{
		Stopwatch = new Stopwatch();
		SerialPort = new SerialPort();
		SerialPort.PortName = "COM4";
		SerialPort.BaudRate = 9600;
		SerialPort.DataBits = 8;
		SerialPort.Parity = Parity.None;
		SerialPort.StopBits = StopBits.One;
		SerialPort.DataReceived += OnReceivedData;
		Stopwatch.Start();
		SerialPort.Open();
	}
	void OnReceivedData(object sender, SerialDataReceivedEventArgs e)
	{
		SerialPort sp = (SerialPort)sender;
		string indata = sp.ReadExisting();

		Stopwatch.Stop();
		var elapsed = Stopwatch.ElapsedMilliseconds;
		Stopwatch.Start();
		Debug.WriteLine(elapsed.ToString());
	}
}