You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[2-[(2,2-dimethyl-3H-1-benzofuran-7-yl)oxy]ethyl]-3-ethyl-2-(2-oxo-2-pyrrolidin-1-ylethyl)guanidine is the IUPAC name of a molecule. Please give its molecular formula.
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