context: LaserDisc was first available on the market, in Atlanta, Georgia, on December 15, 1978, two years after the introduction of the VHS VCR, and four years before the introduction of the CD (which is based on laser disc technology). Initially licensed, sold, and marketed as MCA DiscoVision (also known as simply "DiscoVision") in North America in 1978, the technology was previously referred to internally as Optical Videodisc System, Reflective Optical Videodisc, Laser Optical Videodisc, and Disco-Vision (with a dash), with the first players referring to the format as "Video Long Play".
question: VHS విడుదలై ఎన్ని సంవత్సరాలు గడిచింది?
answers: two years