You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[5-[6-amino-2-[4-(trifluoromethoxy)anilino]purin-9-yl]cyclohexa-2,4-dien-1-yl]prop-2-enamide by IUPAC nomenclature, provide its molecular formula.
user
C21H18F3N7O2
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