You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(4-oxo-2,3,3a,5-tetrahydro-1H-pyrrolo[1,2-a]quinoxalin-2-yl)-2,2-diphenylacetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C25H23N3O2
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