import java.net.*;
import java.io.*;
public class Server extends Thread
{
  public static void main(String[] args)
  {
    
      recv();
    
  }
  public static void recv()
  {
    try {
      DatagramSocket ds=new DatagramSocket(6000);
      byte[] buf=new byte[100];
      DatagramPacket dp=new DatagramPacket(buf,100);
      ds.receive(dp);
      System.out.println(new String(buf,0,dp.getLength()));
      String str="Welcome you!";
      DatagramPacket dpSend=new DatagramPacket(str.getBytes(),str.length(),
                                           dp.getAddress(),dp.getPort());
      ds.send(dpSend);
      ds.close();
    }
    catch (Exception ex) {
      ex.printStackTrace();
    }
  }
  
  }