The aggravated arson statute (Pen. Code, sec. 451.5, subd. (a)(3)), requires damage to five or more inhabited structures, which in turn is defined as a “building,” among other things. A building is a “covered structure that stands predominately by itself and appears more separate and distinct from any other structure than connected to and a part of another structure.” Thus there was insufficient evidence to support appellants conviction for aggravated arson where six apartments were damaged, but they were virtually identical units in a two-story structure; the upper units shared a common roof and their floors were connected to the lower units ceilings, and the units shared common walls.