I (almost) always fall victim of one-off errors in competitive programming when working with counting numbers in range. Sticking to convention like 2 ≤ i < 13,

I (almost) always fall victim of one-off errors in competitive programming when working with counting numbers in range. Sticking to convention like 2 ≤ i < 13, as Dijkstra observed for Mesa programmers, sounds like a good idea.