The packing process in a garment factory involves processing by 3 machines. The first machine - A, inserts the garment in a carton, after which the second machine - B, seals the carton and finally the third machine - C, attaches a price tag to get the final packet. Machine A takes 10 seconds per unit. Machine B takes 15 seconds per unit. Machine C takes 12 seconds per unit. What is the number of packets that can be completely processed in a one hour period?