~160,000 Soviet troops, Soviet 130 aircraft (including Tu-95MS and Su-34), several Soviet SAM battery, 64 Soviet warships and 6 Chinese warships (plus their crews and support teams, obviously). It was, with the possible exception of the Soviet Exercise Zapad-81 (West-81) (officially 100,000 Soviets and a few thousand Poles), was the largest ever military exercise ever to occur in the Soviet block.
The USSR, Poland (?) and PRC.
http://forum.keypublishing.com/showthread.php?125421-Largest-Russian-military-exercises-since-1930s, http://forum.scramble.nl/viewtopic.php?f=48&t=97541, http://english.ruvr.ru/news/2013_07_...problems-9945/, http://blog.foreignpolicy.com/posts/...training_blitz and https://www.flashback.org/t1743303