(b) of section 21-82 , prior to delivering a written notice to the resident specifying the acts or omissions constituting the breach and that the rental agreement shall terminate upon a date not less than thirty days after receipt of the notice. If such breach can be remedied by repair by the resident or payment of damages by the resident to the owner and such breach is not so remedied within twenty-one days, the rental agreement shall terminate except that (A) if the breach is remediable by repairs or the payment of damages and the resident adequately remedies the breach within said twenty-one-day period, the rental agreement shall not terminate, or (B) if substantially the same act or omission for which notice was given recurs within six months, the owner may terminate the rental agreement in accordance with the provisions of sections 47a-23 to 47a-23b , inclusive. For the purposes of this subdivision, “serious nuisance” means