You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,4R,5S)-5-(4-chlorophenyl)-1,2-dimethyl-4-(pyridin-2-ylmethylcarbamoyl)pyrrolidine-2-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H22ClN3O3
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