Russian engineer got fed up of having all responsibility and low salary, so he moves to another city and pretends to be an ordinary worker, same salary and peace of mind. However, not long after communist party sends him to evening classes. On his first day there at maths class he was asked about circle circumference formula, but for some reason he could not remember it off hand, so he goes on blackboard and tries to work it out with linear integral. After exhausting whole blackboard he finally gets the result:
-2RPi
Then all of the sudden he hears all of the class whispering to him: "Change the direction of integration!"