import java.net.*;
import java.io.*;
import java.util.*;

public class ChatServer
{
	private ServerSocket server;
	
	public ChatServer(int port)
	{
		try
		{
			server = new ServerSocket(port);
			server.setReuseAddress(true);
			
			while(true)
			{
				Socket sock = server.accept();
				
				(new Client(sock)).start();
			}
		}
		catch(IOException ioe){ioe.printStackTrace();}
	}
	
	private class Client extends Thread
	{
		private Socket socket;
		private BufferedReader in;
		private PrintStream out;
		private String username;
		
		public Client(Socket s) throws IOException
		{
			socket = s;
			in = new BufferedReader(new InputStreamReader(socket.getInputStream()));
			out = new PrintStream(socket.getOutputStream());
		}
		
		public void run()
		{
			String line;
			try
			{
				while(true)
				{
					line = in.readLine();
					if(username == null)
					{
						username = line;
						continue;
					}
					
					System.out.println(username + ": " + line);
				}
			}
			catch(SocketException se) {}
			catch(IOException ioe){ioe.printStackTrace();}
			
			try
			{
				in.close();
				out.close();
				socket.close();
			}
			catch(IOException ioe){ioe.printStackTrace();}
		}
	}
	
	public static void main(String[] args)
	{
		new ChatServer(Integer.parseInt(args[0]));
	}
}