You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 7-acetyl-1-(2,2-dimethylpropyl)-5-naphthalen-1-yl-5H-4,1-benzothiazepin-2-one by IUPAC nomenclature, provide its molecular formula.
user
C26H27NO2S
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