You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 1,3-benzodioxol-5-yl-[(5S)-3-benzyl-5-methyl-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazin-7-yl]methanone is given. What is its corresponding molecular formula?
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C21H20N4O3
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