You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-benzyl-4-(3,4-diethoxyphenyl)-3-phenyl-1,4-dihydropyrrolo[3,4-c]pyrazol-6-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H27N3O3
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