You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[(3R)-3-(methylsulfanylmethyl)pyrrolidin-1-yl]-3-(4-pyridin-2-ylpiperazin-1-yl)propan-1-one into its molecular formula.
user
C18H28N4OS
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