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system
Name the molecular formula for the molecule established as 4-(3,4-dichlorophenyl)-5-(5,6,7,8-tetrahydro-[1,2,4]triazolo[1,5-a]pyridin-6-yl)-1,2,3,4-tetrahydroisoquinoline using the IUPAC nomenclature.
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C21H20Cl2N4
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