The 100th Shipborne Fighter Aviation Regiment  was formed at Saki in the Crimea on 10 March 1986. In January 1992 its personnel refused to take the oath of loyalty to Ukraine, which would have presumably made them part of the Ukrainian Navy or Ukrainian Air Force, and instead its personnel left for Russia, leaving their aircraft and equipment behind. The unit regrouped at Severomorsk-3 as part of the Northern Fleet. However, in February 1993 the regiment was disbanded and its personnel and equipment incorporated into the 279th Shipborne Fighter Aviation Regiment. The 279th Independent Shipborne Assault Aviation Regiment was established in 1973. In 1990 it became a Maritime Assault Aviation Regiment. On 22 February 1993 it was renamed the 279th Shipborne Fighter Aviation Regiment as it absorbed the remaining elements of the 100th Shipborne Fighter Aviation Regiment.
Question: How many years did the 100th Shipborne Fighter Aviation Regiment and the 279th Shipborne Fighter Aviation Regiment both exist independently?
Answer: 7