You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(2,4-dimethylphenyl)-4-[1-(4-phenoxybutyl)benzimidazol-2-yl]pyrrolidin-2-one;chloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C29H31ClN3O2-
assistant