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

class UDPServer {
    public static void main(String args[]) throws Exception
    {
	DatagramSocket serverSocket = new
	    DatagramSocket(6789);

	byte[] sendData = new byte[1024];

	while(true) {
	    byte[] receiveData = new byte[1024];

	    DatagramPacket receivePacket =
		new DatagramPacket(receiveData, 
				   receiveData.length);
	    serverSocket.receive(receivePacket);

	    String sentence = new String(receivePacket.getData());

	    InetAddress IPAddress = receivePacket.getAddress();

	    int port = receivePacket.getPort();

	    String capitalizedSentence = sentence.toUpperCase();

	    sendData = capitalizedSentence.getBytes();

	    DatagramPacket sendPacket =
		new DatagramPacket(sendData, sendData.length, 
				   IPAddress, port);
	    serverSocket.send(sendPacket);
	}
    }
}