You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl (2R)-1-[2-[(3-methylthiophen-2-yl)methylamino]-2-oxoethyl]pyrrolidine-2-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C14H20N2O3S
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