You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named N-[1-(1H-benzimidazol-2-yl)ethyl]-2-[(4-bromophenyl)sulfonyl-methylamino]acetamide is given. What is its corresponding molecular formula?
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C18H19BrN4O3S
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