40 B-52s
In the end it turned out to be approximately a dozen planes.
The worst fears did not come true - that two A-50 AWACS planes were destroyed. The Ukrainians released footage, and you can see there that they targeted two rusty old planes that were in storage. It's not even clear from the footage what happened to the planes.
Also, no Tu-160s were damaged or destroyed.
Only Tu-95s, Tu-22s, and a single An-12 transport.
I don't understand why Ukraine's officials continue to constantly inflate their achievements. If they had said that they destroyed 12 Russian bombers it still would have had a shocking effect, and would still be hugely embarrassing to Russia.
By needlessly lying, they only damage their own credibility.