You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named N-(1H-benzimidazol-2-ylmethyl)-8-bromo-2-(2,6-dimethylmorpholin-4-yl)pyrazolo[1,5-a][1,3,5]triazin-4-amine by IUPAC nomenclature, provide its molecular formula.
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C19H21BrN8O
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