You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-cyclopropyl-N-[(3S,4S)-4-methyl-1-[4-[2-(methylamino)-2-oxoethyl]benzoyl]pyrrolidin-3-yl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H27N3O3
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