(by rule 1 on the leftmost ) (by rule 2 on the leftmost ) (by rule 1 on the leftmost ) (by rule 2 on the leftmost ) (by rule 3 on the leftmost ),
(by rule 1 on the leftmost ) (by rule 2 on the leftmost ) (by rule 1 on the leftmost ) (by rule 2 on the leftmost ) (by rule 3 on the leftmost )