You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named N-[5-[(1,3-dioxo-5,6,7,7a-tetrahydropyrrolo[1,2-c]imidazol-2-yl)methyl]-2-methoxyphenyl]-3-fluorobenzamide by IUPAC nomenclature, provide its molecular formula.
user
C21H20FN3O4
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