So we take a breath and at this position we begin to forcefully exhale the remaining air. And at the maximum point of the forceful exhalation, we're going to be at this location and the distance from this purple line all the way to the top. This distance here is known as the vital capacity. And the vital capacity is equal to about 4800 air per breath. So essentially, if we forcefully exhale our air, we're going to end up in this region. And then if we try to actually forcefully inhale as much air as possible, we're going to go from this location all the way to this location and the amount of air that will be exchanged by the lungs during that process is equal to 4800.