A metal junction box is a trade size of 4″ x 1 1/2″ square. It contains 4 size 12 AWG circuit conductors (2 pair) spliced together, and a flat cover. There are no devices or clamps mounted in the box. Additional size 12 AWG conductors need to be added to the box. What is the maximum number of size 12 AWG conductors that may be added to this box?