You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named [2-[3-[3-(1H-benzimidazol-2-yl)-3-oxopropyl]-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-6-yl]phenyl] acetate by IUPAC nomenclature, provide its molecular formula.
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C21H16N6O3S
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