Hi! I'm a rookie programmer, and I just want to try my hand at competitive coding here at Codeforces. I've read that in contests, you are supposed to "hack" other people's solutions to reveal weaknesses in their code. Does this mean coders should build their code to handle cases which may break the preconditions? For example, if the problem has pure numeric input, should users take the time to handle exceptions for non-numeric input values?