You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[1-(chloromethyl)-2-oxopyridin-4-yl]-2-(4-fluoro-2-methylphenoxy)-4-(trifluoromethyl)benzamide into its molecular formula.
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C21H15ClF4N2O3
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