You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(4-chloro-3-quinoxalin-2-ylphenyl)-5-methyl-2-(trifluoromethyl)furan-3-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C21H13ClF3N3O2
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