You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3,3,5,5-tetramethyl-1-oxido-1-[1-(3,3,5,5-tetramethyl-1-oxidopiperazin-1-ium-1-yl)ethyl]piperazin-1-ium The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H38N4O2
assistant