You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (6S,9S)-5-acetyl-9-(4-methylphenyl)-6-pyridin-3-yl-6a,8,9,10-tetrahydro-6H-benzo[b][1,4]benzodiazepin-7-one by IUPAC nomenclature, provide its molecular formula.
user
C27H25N3O2
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