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 7-[2-[(2S)-2,3,3a,4,5,6,7,7a-octahydro-1H-indol-2-yl]-3H-benzimidazol-5-yl]-N,9,9-trimethylfluoren-2-amine is given. What is its corresponding molecular formula?
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C31H34N4
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