of one of the greatest natural sportsmen of modern times 
(ROOT (PP (IN of) (NP (NP (CD one)) (PP (IN of) (NP (NP (DT the) (JJS greatest) (JJ natural) (NNS sportsmen)) (PP (IN of) (NP (JJ modern) (NNS times))))))))
(ROOT (PP (IN ) (NP (NP (CD )) (PP (IN ) (NP (NP (DT ) (JJS ) (JJ ) (NNS )) (PP (IN ) (NP (JJ ) (NNS ))))))))