You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3R)-1-benzyl-5-bromo-3-[2-(2,5-dimethylphenyl)-2-oxoethyl]-3-hydroxyindol-2-one by IUPAC nomenclature, provide its molecular formula.
user
C25H22BrNO3
assistant