Various open sources place the total current Russian troop deployment at around 40,000. We know that Edward Snowden is working with the Russian government (remember the good old days when we’d shoot traitors?) and because of this the Russians probably have a better idea of how to evade US satellites (and shall we say “other” intelligence assests) that are currently monitoring the Russian military. I think a safe bet would be to add at least 30% to the open-source number.
Just my opinion anyway.