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 N-[4-[2-(2',5'-dioxospiro[2,3-dihydrochromene-4,4'-imidazolidine]-1'-yl)acetyl]phenyl]propanamide is given. What is its corresponding molecular formula?
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C22H21N3O5
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