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 tert-butyl N-(7-bromo-2,3,4,9-tetrahydro-1H-carbazol-3-yl)-N-methylcarbamate is given. What is its corresponding molecular formula?
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C18H23BrN2O2
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