You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-fluoro-4-[3-(4-isocyano-3-methylphenyl)-5,5-dimethyl-2,4-dioxoimidazolidin-1-yl]-N-methylbenzamide into its molecular formula.
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C21H19FN4O3
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