(S (S (S (PP (IN After) (S (VP (VP (VBG searching) (NP (BASENP (NN 644) (NN square) (NNS miles)) (PP (IN of) (BASENP (NN ocean))))) (PP (IN with) (BASENP (NN nine) (NN aircraft)))))) (S (BASENP (NN debris)) (VP (VBZ has) (VP (VBN been) (VP (VBN located) (PP (IN from) (BASENP (PDT both) (DT the) (NN aircraft)))))))) (CONJP (COMMA ,) (CC but)) (S (BASENP (DT no) (NN trace)) (VP (VBZ has) (VP (VBN been) (VP (VBN found) (PP (IN of) (NP (BASENP (DT those)) (PP (IN on) (BASENP (NN board)))))))))) (PERIOD .))