You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-cyclobutyl-8-(4-ethylphenyl)-1,2,4,5-tetrahydro-[1,4]diazepino[1,7-a]benzimidazole The above is the IUPAC name of a molecule. Write its molecular formula.
user
C23H27N3
assistant