Grant leased an apartment to Epstein for the term May 1, 2010, to April 30, 2011, at $750 a month ‘‘payable in advance on the first day of each and every month of said term.’’ At the time the lease was signed, Epstein told Grant that he received his salary on the tenth of the month and that he would be unable to pay the rent before that date each month. Grant replied that would be satisfactory. On June 2, due to Epstein’s not having paid the June rent, Grant sued Epstein for such rent. At the trial, Epstein offered to prove the oral agreement as to the date of payment each month. Is the oral evidence admissible?