You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 4-butyl-5-methylnaphtho[2,3-c]carbazole;4,5-dimethylnaphtho[2,3-c]carbazole;5-methyl-4-pentylnaphtho[2,3-c]carbazole;5-methyl-4-propylnaphtho[2,3-c]carbazole is given. What is its corresponding molecular formula?
user
C141H120N6
assistant