NYC alone has more than 300000 first generation Jewish immigrants from Russia and Ukraine who has relatives back to home countries. There are might be few people identifying as Jewish due to a traditional securalism an left-lean of them in that part of the World but they are certainly in millions.
Perhaps millions who have a distant ancestor who was Jewish, but identifiably Jewish today? Not a chance!
No source finds as many as a million Jews (even by the broadest definitions) left in the countries of the former Soviet Union.