You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl (1S)-1-[(2-amino-4-iodophenyl)methyl]-6,7-dimethoxy-3,4-dihydro-1H-isoquinoline-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H25IN2O4
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