Answer:
The word hat is the adverb modifying another adverb is "not"
Explanation:
An adverb modifies another adverb or a verb, then "not" is an adverb because it changes the meaning of the verb from positive to negative, in this sentence the adverb that is being modified by the use of "not" is "exactly", moving it from positive to negative where what happened was the total opposite from what the person was expecting.
