at once disarmingly straightforward and strikingly devious . 
(ROOT (S (PP (IN at) (RB once)) (ADJP (ADJP (RB disarmingly) (JJ straightforward)) (CC and) (ADJP (RB strikingly) (JJ devious))) (. .)))
(ROOT (S (PP (IN ) (RB )) (ADJP (ADJP (RB ) (JJ )) (CC ) (ADJP (RB ) (JJ ))) (. )))