(S (S (NP (BASENP (NN Two)) (PP (IN of) (BASENP (DT the) (NNS protesters)))) (VP (VP (VBD photographed) (BASENP (PRP themselves))) (PP (IN atop) (NP (BASENP (DT a) (NN building)) (PP (IN inside) (BASENP (DT the) (NN spy) (NN base))))))) (PERIOD .))