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-(3-chlorophenyl)ethyl]-4-[[2-(1-methylimidazol-2-yl)sulfanylacetyl]amino]benzamide is given. What is its corresponding molecular formula?
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C21H21ClN4O2S
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