You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-1'-(5-amino-1-tert-butylpyrazole-4-carbonyl)-6-chloro-5-fluorospiro[1H-3,1-benzoxazine-4,3'-piperidine]-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H23ClFN5O3
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