You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-acetyl-6-(1,3-benzodioxol-5-yl)-10-bromo-3-ethylsulfanyl-2,6-dihydro-[1,2,4]triazino[1,6-c]quinazolin-5-ium-1-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H18BrN4O4S+
assistant