import java.awt.Color;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import java.io.File;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

import javax.swing.*;

public class Control  implements KeyListener {
    public void keyPressed(KeyEvent e) {}
    public void keyReleased(KeyEvent e) {}
    public static void main(String[] args) {
        new Control();
    }

    JFrame frame;
    JTextField firstNumber = new JTextField();
    JTextField secondNumber = new JTextField();
    JTextArea result = new JTextArea();


    public Control() {
        frame = new JFrame();
        frame.setLayout(null);

        firstNumber.addKeyListener(this);
        secondNumber.addKeyListener(this);

        firstNumber.setBounds(50, 50, 300, 30);
        secondNumber.setBounds(50, 90, 300, 30);
        result.setBounds(50, 140, 300, 300);

        frame.add(firstNumber);
        frame.add(secondNumber);
        frame.add(result);

        frame.setSize(550,800);
        frame.setVisible(true);
    }


    public void keyTyped(KeyEvent e) {

        if(isInteger(firstNumber.getText()) && isInteger(secondNumber.getText()) ){
            String value = firstNumber.getText() + secondNumber.getText();
            String reverse = new StringBuilder(value).reverse().toString();
            result.setText(reverse);
        }

    }
    public boolean isInteger( String input ){
       try{
          Integer.parseInt( input );
          return true;
       }
       catch( NumberFormatException e ){
          return false;
       }
    }



}