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

public class srv {

static String port = "5194";

public static void main(String[] argv) {
    if (argv.length == 0)
        srv(port);
    else
        srv(argv[0]);
}

public static void srv(String port) {    // tcp/ip version
    try {
        ServerSocket server = new ServerSocket(Integer.parseInt(port));
        while (true) {
            Socket sock = server.accept();
System.err.println("srv " + sock);
            echo(sock);
            sock.close();
        }
    } catch (IOException e) {
        e.printStackTrace();
    }
}

static void echo(Socket sock) throws IOException {
    DataInputStream in = 
        new DataInputStream(sock.getInputStream());
    DataOutputStream out = 
        new DataOutputStream(sock.getOutputStream());
    String s;

    while ((s = in.readLine()) != null) {
        out.writeBytes(s);
        out.writeByte('\n');
        out.flush();
        if (s.equals("exit"))
            break;
    }
}

}