Recently, gallium nitride (GaN) has been used to make light-emitting diodes (LEDs) that emit a blue or ultraviolet light. Such LEDs are used in DVD players and other electronic devices. This material has two crystal structures. One form is the zinc-blende crystal structure (lattice constant a0 = 0.450 nm), which has a density of 6.1 g/cm3 at 300 K. Calculate the number of Ga and N atoms per unit cell of this form of GaN.