You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 1-[9-methoxy-7-(4-methylphenyl)-3,5-dihydro-2H-1,4-benzoxazepin-4-yl]propan-1-one is given. What is its corresponding molecular formula?
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C20H23NO3
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