You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 6-[(3R)-3-aminopiperidin-1-yl]-5-[(2-chloro-5-fluorophenyl)methyl]-2,3-dimethyl-4-oxopyrrolo[3,2-d]pyrimidine-7-carbonitrile ?
user
C21H22ClFN6O
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