thirteen conversations about one thing , for all its generosity and optimism , 
(ROOT (S (NP (NP (CD thirteen) (NNS conversations)) (PP (IN about) (NP (CD one) (NN thing)))) (, ,) (PP (IN for) (NP (PDT all) (PRP$ its) (NN generosity) (CC and) (NN optimism))) (, ,)))
(ROOT (S (NP (NP (CD ) (NNS )) (PP (IN ) (NP (CD ) (NN )))) (, ) (PP (IN ) (NP (PDT ) (PRP$ ) (NN ) (CC ) (NN ))) (, )))