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system
Name the molecular formula for the molecule established as (9aR)-N-[2-(4-methyl-1H-benzimidazol-2-yl)ethyl]-9-oxo-3,4,6,7,8,9a-hexahydro-1H-pyrazino[1,2-a]pyrazine-2-carboxamide using the IUPAC nomenclature.
user
C18H24N6O2
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