(S (S (NP (NP (BASENP (DT The) (NN number)) (PP (IN of) (BASENP (VBN destroyed) (NNS houses)))) (PP (IN in) (BASENP (NNP Nias)))) (VP (VBZ is) (VP (VBN estimated) (PP (IN at) (BASENP (NN 4) (NN 500)))))) (PERIOD .))