You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 7-[2,6-difluoro-3-methoxy-5-(methoxymethyl)phenyl]spiro[3,6-dihydropyrrolo[2,3-c][2,7]naphthyridine-9,1'-cyclopropane]-8-one by IUPAC nomenclature, provide its molecular formula.
user
C21H19F2N3O3
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