You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[(2S)-1-[4-(benzimidazol-1-yl)anilino]-1-oxopropan-2-yl]-5-bromothiophene-2-carboxamide into its molecular formula.
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C21H17BrN4O2S
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