You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 1-[N-ethyl-N'-[4-(4-methyl-1,3-thiazol-2-yl)butyl]carbamimidoyl]-4-methylpyrrolidine-3-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H30N4O2S
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