(S (S (BASENP (DT The) (NNS peacekeepers)) (VP (VBP are) (NP (BASENP (NN part)) (PP (IN of) (NP (BASENP (DT a) (ADJP (JJ joint) (JJ African)) (NNP Union-U.N.) (NN mission)) (VP (VBN aimed) (PP (IN at) (S (VP (VP (VBG putting) (BASENP (NN 26,000) (NNS troops))) (PP (IN in) (BASENP (DT the) (NN region)))))))))))) (PERIOD .))