You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4R)-4-[1-[2-(2,5-dimethylphenoxy)ethyl]benzimidazol-2-yl]-1-(2-fluorophenyl)pyrrolidin-2-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H26FN3O2
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