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

public class ProtectedServer
{
	public boolean authenticate(InputStream inStream) throws IOException, NoSuchAlgorithmException 
	{
		DataInputStream in = new DataInputStream(inStream);

		// IMPLEMENT THIS FUNCTION.
	}

	protected String lookupPassword(String user) { return "abc123"; }

	public static void main(String[] args) throws Exception 
	{
		int port = 7999;
		ServerSocket s = new ServerSocket(port);
		Socket client = s.accept();

		ProtectedServer server = new ProtectedServer();

		if (server.authenticate(client.getInputStream()))
		  System.out.println("Client logged in.");
		else
		  System.out.println("Client failed to log in.");

		s.close();
	}
}