You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (3aS,6S,7aR)-6-(cyclopropylmethoxy)-3a-methoxy-1-[(2-methoxyphenyl)methyl]-3,4,5,6,7,7a-hexahydro-2H-indole into molecular formula.
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C21H31NO3
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