You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 1-[4,5-diethyl-1,3-di(propan-2-yl)imidazol-1-ium-2-yl]sulfanylbutan-2-one by IUPAC nomenclature, provide its molecular formula.
user
C17H31N2OS+
assistant