Statement

Edoardo has decided to improve the current password generator for the OIS, in order to obtain passwords that are even more secure and easy to remember at the same time! Of course, this is not an easy task. He decided that the best way to generate such a password (with respect to a given language consisting of N words W_i for i=0 … N-1) is to find a string P of length L such that: (1) consistency: every substring of P of length K appears in some word of the given language; (2) novelty: every substring of P of length K+1 does not appear in any word of the given language. Help Edoardo find such a word!