So eventually the pressure on the right side will decrease, the pressure on the left side will increase and the pressure on the left side will become greater than the pressure on the right side of the heart. And when that takes place, that's when the foramino valley closes. So remember the septum prima, this wall will only open this way when the pressure inside the right atrium is higher than the pressure inside the left atrium. But as soon as the first breath is taken, the pressure inside the right atrium drops, the pressure inside the left atrium increases. And so we have a reversal of the pressure differential. And now, because the pressure on the left side of the atrium is greater, it will create a force that will point in this direction and that will close, shut this for a minute or valley.