(S (S (PP (VBG According) (PP (TO to) (NP (BASENP (NNP Gabon) (POS 's)) (NN constitution)))) (COMMA ,) (S (S (NP (BASENP (DT the) (NN president)) (PP (IN of) (BASENP (DT the) (NN senate)))) (VP (VBZ is) (S (VP (TO to) (VP (VB become) (BASENP (DT the) (JJ interim) (NN ruler))))))) (SINV (MD should) (S (S (BASENP (DT the) (NN president)) (VP (VB die))) (SBAR (IN while) (SBAR (PP (IN in) (BASENP (NN office))))))))) (PERIOD .))