One down, eight more to go.
FWIW:
https://en.wikipedia.org/wiki/Beriev_A-50
After completing the joint state tests, Beriev has delivered the first A-50U to the Russian Air Force.
The aircraft, “47 Krasnyy’”RF-92957, was handed over at Beriev’s facility in Taganrog on 31 October 2011.
It was accepted by an aircrew serving with the 2457th Aviation Base for Combat Operation of Airborne Early Warning Aircraft (Aviabaza Boevogo Primeneniya Samolyotov Dal’nego Radiolokatsionnogo Obnaruzheniya) at Ivanovo Severny, which is the only base using the A-50 operationally (it operates 16 aircraft).
The fourth A-50U, “41 Taganrog”, was delivered to the Russian Aerospace Forces on 7 March 2017. The fifth A-50U, “45 Krasnyy”, was delivered on 6 December 2018. 7 aircraft have been delivered as of December 2021.