DouKaku?

using System;
using System.IO;
using System.Net.Sockets;

class P
{
    static void Main(string[] args)
    {
        TcpClient c = new TcpClient(args[0], int.Parse(args[1]));
        NetworkStream s = c.GetStream();
        TextWriter w = new StreamWriter(s);
        TextReader r = new StreamReader(s);
        string l = null;
        while ((l = Console.ReadLine()) != null)
        {
            w.WriteLine(l);
            w.Flush();
            Console.WriteLine(r.ReadLine());
        }
    }
}