You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[2-(4-chlorophenyl)ethyl]-2-[(4S)-4-methyl-4-(4-methylphenyl)-2,5-dioxoimidazolidin-1-yl]acetamide into its molecular formula.
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C21H22ClN3O3
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