You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[4-[(3-fluorophenyl)methylamino]-5-methylpyrimidin-2-yl]-2-methylbenzimidazole-4-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C21H19FN6O
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