 Complete the following phrase:  The R-2s were assigned to the 1st Armoured Regiment of the 1st Armoured Division where they participated in Operation Barbarossa. The division was withdrawn from combat after the Battle of Odessa in 1941. At the start of 1942, 40 tanks were sent to Pilsen for overhaul while 50 more were repaired in Ploiești. The division returned to the front on 29 August 1942 with 109 R-2s. By the eve of the Soviet 