Task: Question Generation
Input (English): Passage: In 1989, the 126th Motor Rifle Division at Simferopol was transferred to the Black Sea Fleet from the Odessa Military District. Also that year, the 119th Fighter Aviation Division, with the 86th Guards, 161st, and 841st Guards Fighter Aviation Regiments, joined the Fleet from the 5th Air Army.  The 86th Guards Fighter Aviation Regiment became part of the Moldovan Air Force upon the breakup of the Soviet Union. The 841st at Meria airport   became the 841st independent Guards Anti-Submarine Helicopter Regiment in May 1991 and was disbanded in October 1992.
Output (English): How many years was the 841st Meria airport become 841st independent Guards Anti Submarine Helicopter Regiment?