And by Boils law, when we decrease our volume, we increase our pressure as long as the temperature is allowed to be constant. And so what happens is, because the pressure inside our intraplural space drops, eventually the pressure inside the intraplural space at the end of that relaxation where when we're at this point, the pressure inside the intraplural space will be greater than the pressure outside of our environment so outside of the body and inside the lung. And in that case, that pressure gradient will force the air to move from the lungs to the outside. And at that point, these two quantities are switched. So when we're exhaling, the pressure inside the intraplural space is greater than the pressure in the outside environment, our atmosphere pressure. And so at that point, when we're right here, we have exhalation taking place.