class DgramUtils {
    public DatagramPacket buildPkg(InetAddress addr, int port, String msg) throws IOException {
        ByteArrayOutputStream bstream = new ByteArrayOutputStream();
        DataOutputStream dstream = new DataOutputStream(bstream);
        byte[] data;
        dstream.writeUTF(msg);
        data = bstream.toByteArray();
        return new DatagramPacket(data, data.length, addr, port);
    }
    public String getCont(DatagramPacket pkg) throws IOException {
        DataInputStream dstream = new DataInputStream(
                    new ByteArrayInputStream(pkg.getData(), 0, pkg.getLength())
        );
        return dstream.readUTF();
    }
        return dstream.readUTF();
    }
}
public class server {
    public static final int port = 3333;
    private static void print(String msg) {
        System.out.println(msg);
    }
    private static int cubo(int n) {
        return (int)Math.pow(n, 3);
    }
    public static void main(String[] args) {
        System.setProperty("java.net.preferIPv4Stack" , "true");
        DgramUtils du = new DgramUtils();
        byte[] buf = new byte[100];
        DatagramSocket sock = null;
        try {
            sock = new DatagramSocket(port);
        try {
            sock = new DatagramSocket(port);
        } catch (SocketException e) {
            server.print("sock err: " + e.getMessage());
            System.exit(1);
        }
        while (true) {
            try {
                DatagramPacket pkg = new DatagramPacket(buf, buf.length);
                String cont;
                int n;
server.print("rec");
                sock.receive(pkg);
server.print("arec");
                cont = du.getCont(pkg);
                n = server.cubo(Integer.parseInt(cont));
                buf = Integer.toString(n).getBytes();
                pkg = new DatagramPacket(buf, buf.length, pkg.getAddress(), pkg.getPort());
server.print("rec " + n+" buf "+buf);
                sock.send(pkg);
                Arrays.fill(buf, (byte)0);
                Arrays.fill(buf, (byte)0);
            } catch (IOException e) {
                e.printStackTrace();
                continue;
            } catch (Exception e) {
                server.print("unk err: " + e.getMessage());
                sock.close();
                System.exit(1);
            }
        }
    }
}