You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 1-(2-methyl-2,3-dihydroindol-1-yl)-2-(1,3,3-trimethyl-6-azabicyclo[3.2.1]octan-6-yl)ethane-1,2-dione by IUPAC nomenclature, provide its molecular formula.
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C21H28N2O2
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