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 (3aR,8aR)-1'-(morpholin-4-ium-4-ylmethyl)spiro[4,5,6,7,8,8a-hexahydro-3aH-cyclohepta[d][1,3]dioxole-2,3'-indole]-2'-one is given. What is its corresponding molecular formula?
user
C20H27N2O4+
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