You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2,4-dichloro-N-(3,3-dimethyl-4-oxo-2,5-dihydro-1,5-benzoxazepin-7-yl)benzamide by IUPAC nomenclature, provide its molecular formula.
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C18H16Cl2N2O3
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