[tag=DT] [lemma=means] [word=a] [lemma=total] [lemma=□]
[tag=DT] [lemma=means] [word=a] [lemma=total] [lemma=of]
[tag=DT] [lemma=means] [word=a] [lemma=total] [lemma=means]
This means a total of at least seven years of previous preparation .