(S (S (BASENP (DT The) (NNP United) (NNPS States)) (VP (VP (CC neither) (VP (VBZ confirms) (CC nor) (VBZ denies))) (NP (BASENP (DT the) (NN existence)) (PP (IN of) (BASENP (JJ secret) (NN detention) (NNS centers)))))) (PERIOD .))