You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-pyrrolidin-1-yl-5-[2-(5,6,7,8-tetrahydro-4H-pyrazolo[1,5-a][1,4]diazepin-2-yl)imidazol-1-yl]benzonitrile into its molecular formula.
user
C21H23N7
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