You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance (3S)-1'-(5,7-dimethylpyrazolo[1,5-a]pyrimidine-3-carbonyl)spiro[1H-indole-3,3'-piperidine]-2-one .
user
C21H21N5O2
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