on his perch , This <apostrophe>m so silly .
(ROOT_0 (S_0 (ATS_3 (ATS_1 (ATS_2 (PP_2 (IN_0 on) (NP_3 (PRPDOLLAR_0 his) (NN_0 perch))) (COMMA_0 ,)) (NP_0 (DT_1 This))) (VP_3 (VBP_0 <apostrophe>m) (ADJP_0 (RB_0 so) (JJ_0 silly)))) (DOT_0 .)))