Editorial for Another Contest 5 Problem 1 - Goat Fence
Submitting an official solution before solving the problem yourself is a bannable offence.
With the bounds as low as they are, several different solutions were possible. One approach is to brute force over all pairs of side lengths ~l~ and ~w~ where ~1 \le l, w \le N~ and list out the rectangle with the maximum perimeter - with ~N \le 100~, this solution comfortably runs in time.
It follows fairly directly from the problem statement that the maximum perimeter is at least ~2N+2~ - a rectangle with dimensions ~1 \times N~ clearly attains this perimeter. We actually cannot do better than this. Therefore, it suffices to read in ~N~ and print ~2N + 2~.