import javax.swing.*;

public class perimeterDialog
{
  public static void main(String[] args)
  {
    String input, output;
    double length, width, perimeter;

    input = JOptionPane.showInputDialog("Length of box:");
    length = Double.parseDouble(input);

    input = JOptionPane.showInputDialog("Width of box");
    width = Double.parseDouble(input);

    perimeter = 2 * length + 2 * width;

    output = String.format("For the box with length %.2f%n", length)
      + String.format("and width %.2f%n", width)
      + String.format("the perimeter is %.2f%n", perimeter);

    JOptionPane.showMessageDialog(null,
      output,
      "Perimeter of the box.",
      JOptionPane.INFORMATION_MESSAGE);

    System.exit(0);
  }
}