Don't remember. 
( ( ( Do n't ) remember ) . )
(ROOT (S (VP (VB Do) (RB n't) (VP (VB remember))) (. .)))
I do not remember.
( I ( ( ( do not ) remember ) . ) )
(ROOT (S (NP (PRP I)) (VP (VBP do) (RB not) (VP (VB remember))) (. .)))