Used stamps exchanges.

Look at russian stempel in the envelope - the letter arrived to me just now, on 27th of May!
So, the russian post in Moscow is working very slow :(

This is done on purpose. Even my one registered letter to Slovakia traveled to the same airport from Belarus Minsk to Moscow (Vnukovo) 3x a total of 60 days. I watched it. Really unpopular. In doing so, there are direct flights from Minsk to Bratislava (Wien) - delivery of the letter 4 days, but they send it through Moscow, which is a proper siege.