You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule (5S)-5-(4-methoxyphenyl)-5-methyl-3-[(1-methylbenzimidazol-2-yl)methyl]imidazolidine-2,4-dione into molecular formula.
user
C20H20N4O3
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