You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(7R)-N-cyclopentyl-5-(1H-indole-2-carbonyl)-6,7-dihydro-4H-pyrazolo[1,5-a]pyrazine-7-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23N5O2
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