**The first real hint will be published on 9th Ma**y. Meanwhile, here is a small clarification regarding the grading of Problem 5. The mistake is considered to be small (bringing 0.95-penalty) if the solution starts with correct basic assumptions and correct first few steps. The mistake is considered to be major (bringing 0.9-penalty) if the solution starts with incorrect assumptions and incorrect first expressions.

*Please submit the solution of this problem via e-mail to physcs.cup@gmail.com.** *

* For full regulations, see the “Participate” tab.*