Bo is trying to find the height of a radio antenna on the roof of a local building. He stands at a horizontal distance of 20 meters from the building. The angle of elevation from his eyes to the roof (point A) is 18°, and the angle of elevation from his eyes to the top of the antenna (point B) is 42°. If his eyes are 1.57 meters from the ground, find the height of the antenna (the distance from point A to point B). Round your answer to the nearest meter if necessary.