You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 4-[(2S)-2-methyl-4-methylsulfonylpiperazin-1-yl]-6-(trifluoromethyl)-1H-indole by IUPAC nomenclature, provide its molecular formula.
user
C15H18F3N3O2S
assistant