I have a family friend who’s old enough to have served in the Soviet military. The guy is a sharp dude who had really good grades in math. So when he was drafted he was directly enlisted into the ‘rocket force’ as a guy who does the trajectory calculations. He served in Kaliningrad.
He tells that they’d get drills where they are woken up at night, and then need to calculate trajectories for hitting Oslo, Paris, London, etc.