You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(2-ethylsulfonylphenyl)-2-[4-(4-methoxyphenyl)-4-methyl-2,5-dioxoimidazolidin-1-yl]acetamide by IUPAC nomenclature, provide its molecular formula.
user
C21H23N3O6S
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