You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-(2,4-dimethyl-6-nitrophenoxy)-1-(4-pyridin-1-ium-2-ylpiperazin-1-yl)ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H23N4O4+
assistant