You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[(4-bromophenyl)methyl]-4-(4-chlorophenyl)sulfanyl-N-[(2R)-1-oxo-1-(propan-2-ylamino)propan-2-yl]butanamide by IUPAC nomenclature, provide its molecular formula.
user
C23H28BrClN2O2S
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