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

class UDPServer {
   	public static void main (String args[]) throws Exception {

	        // Create Datagram socket at port 7777
	        DatagramSocket serverSocket = new DatagramSocket(7777);

	        byte[] receiveData = new byte[1024];
	        byte[] sendData = new byte[1024];

	        while(true) {
		
		// Create space for received datagram
		DatagramPacket receivePacket = new DatagramPacket(receiveData, receiveData.length);
		
		// Receive datagram
		serverSocket.receive(receivePacket);
                String sentence = new String(receivePacket.getData());

System.out.println("Received from client: " + sentence);
                    
	        // Get IP address of the sender
	        InetAddress IPAddress = receivePacket.getAddress();

	        // Get port number of the sender
	        int port = receivePacket.getPort();
	
	        String capitalizedSentence = sentence.toUpperCase() + '\n';

	        sendData = capitalizedSentence.getBytes();

	        // Create datagram to send to client 
	        DatagramPacket sendPacket = new DatagramPacket(sendData, sendData.length, IPAddress, port);

	       // Write datagram to socket
	        serverSocket.send(sendPacket);

	     } // Loop back and wait for another datagram
	}
     }