I tried this codeforces problem contest/1189/problem/A. Trying a contest problem after many years and I thought, it was a problem either with Dynamic Programming or with Recursion.
Turned out be a much much simpler one, that if a person reads the problem carefully and understands the scope of the solution, the solution can be written in < 2 minutes.
I spent 30 minutes unsuccessfully. Lack of experience shows up if you don't practice.