You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(4S)-2',5'-dioxospiro[2,3-dihydro-1H-naphthalene-4,4'-imidazolidine]-1'-yl]-N-[(S)-(4-methoxyphenyl)-phenylmethyl]acetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H27N3O4
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