You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 2-[3-(thiophene-2-carbonyl)-1-azoniabicyclo[2.2.2]octan-1-yl]acetate;bromide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H22BrNO3S
assistant