You should reply ASAP.
1	You	you	PRON	PRP	Case=Nom|Person=2|PronType=Prs	3	nsubj	3:nsubj	_
2	should	should	AUX	MD	VerbForm=Fin	3	aux	3:aux	_
3	reply	reply	VERB	VB	VerbForm=Inf	0	root	0:root	_
4	ASAP	ASAP	ADV	RB	_	3	advmod	3:advmod	SpaceAfter=No
5	.	.	PUNCT	.	_	3	punct	3:punct	_
