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 (6S,10bR)-6-(3,4,5-trimethoxyphenyl)-1,2,3,5,6,10b-hexahydropyrrolo[2,1-a]isoquinoline is given. What is its corresponding molecular formula?
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C21H25NO3
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