classify as it is hard to resist 
(ROOT (S (VP (VB classify) (SBAR (IN as) (S (NP (PRP it)) (VP (VBZ is) (ADJP (JJ hard) (SBAR (S (VP (TO to) (VP (VB resist))))))))))))
(ROOT (S (VP (VB ) (SBAR (IN ) (S (NP (PRP )) (VP (VBZ ) (ADJP (JJ ) (SBAR (S (VP (TO ) (VP (VB ))))))))))))