You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named 2-(2,5-dioxo-4-propan-2-ylimidazolidin-1-yl)-N-(4-phenylbutan-2-yl)acetamide by IUPAC nomenclature, provide its molecular formula.
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C18H25N3O3
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