You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-(4-chlorophenyl)-5',5',6,6-tetramethylspiro[5,7-dihydro-3H-1-benzofuran-2,2'-cyclohexane]-1',3',4-trione by IUPAC nomenclature, provide its molecular formula.
user
C23H25ClO4
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