You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named (4-methylquinolin-2-yl)-[4-(5,6,7,8-tetrahydro-[1,2,4]triazolo[4,3-a]pyrazin-3-yl)piperidin-1-yl]methanone;dihydrochloride by IUPAC nomenclature, provide its molecular formula.
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C21H26Cl2N6O
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