You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 7-N-[2-(diethylamino)ethyl]-3-N,3-N-diethyl-7-N-methyl-1,10-dihydrophenothiazin-1-ylium-3,7-diamine by IUPAC nomenclature, provide its molecular formula.
user
C23H33N4S+
assistant