 Complete the following phrase:  An official letter concerning the need for destruction of the monument to Mikhail Kalinin and removing his name from the citys toponymy was sent to the Minsk Executive Committee by Belarusian activists in 2010. This was attributed to the fact that Mikhail Kalinin was one of six members of the Soviet Politburo who signed an order to execute 25,700 Polish nationalists and counterrevolutionaries kept at camps and prisons in western Ukraine and Belarus, on 5 March 1940, during the 