Paths having less than z words or that do not contain a verb are filtered out (z is a tuning parameter).
unlike in Boudin and Morin (2013), we rerank the K best paths with the following novel weighting scheme (the lower, the better), and the path with the lowest score is used as the compression: The denominator takes into account the length of the path, and its fluency (F ), coverage (C), and diversity (D).