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 (8S)-1'-(1-methylpyrazole-3-carbonyl)-2-(pyridin-2-ylmethyl)spiro[6,7-dihydropyrrolo[2,1-c][1,2,4]triazine-8,3'-pyrrolidine]-3,4-dione is given. What is its corresponding molecular formula?
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C20H21N7O3
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