You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 6-[5-(2-carbamoylphenyl)pyridin-3-yl]-3,4-dihydro-2H-1,8-naphthyridine-1-carboxamide into its molecular formula.
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C21H19N5O2
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