You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 5-ethyl-4-methyl-N-[3-[(5R)-5-methyl-2-oxoimidazolidin-1-yl]phenyl]furan-2-carboxamide is given. What is its corresponding molecular formula?
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C18H21N3O3
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