import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.ServerSocket;
import java.net.Socket;
class SquareServer {
private final static int BUFSIZE = 20;
public static void main(String args[]) throws Exception {
int port = Integer.parseInt(args[0]);
ServerSocket ss = new ServerSocket(port);
while (true) {
Socket s = ss.accept();
InputStream is = s.getInputStream();
DataInputStream dis = new DataInputStream(is);
double value = dis.readDouble();
value *= value;
OutputStream os = s.getOutputStream();
DataOutputStream dos = new DataOutputStream(os);
dos.writeDouble(value);
s.close();
}
}
}