Based on the line you identified in the previous question, which rule needs to be used in this proof before line $5$ in order to avoid that particular mistake?

Just type the abbreviated name for your answer, without any of the numbers for citation.

If you need any special symbols or rule names, copy$/$paste your answer from here:

&E $,$ &I $,$ vI $,$ DN $,$ MP $,$ MT $,$ A $,$ CP $,$ IP $,$I $,,->,,$

$(-$A $->$ A$)|-$ A