You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by 2-[[2-[4-(3,4-dimethylphenyl)sulfonylpiperazin-1-ium-1-yl]acetyl]amino]-N-ethylacetamide ?
user
C18H29N4O4S+
assistant