You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
methyl 2-bromo-3-[4-[2-(5-ethyl-1-oxidopyridin-1-ium-2-yl)ethoxy]phenyl]propanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H22BrNO4
assistant