You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6S,9S)-6-(3-chloro-5-ethoxy-4-hydroxyphenyl)-9-(4-methylphenyl)-5,6,8,9,10,11-hexahydrobenzo[b][1,4]benzodiazepin-7-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H27ClN2O3
assistant