You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (7-fluoro-2-methylquinolin-3-yl)-(6-methoxy-3,4-dihydro-2H-quinolin-1-yl)methanone by IUPAC nomenclature, provide its molecular formula.
user
C21H19FN2O2
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