You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[(S)-(3,4-dichlorophenyl)-[(3S)-3-methylpiperidin-1-ium-1-yl]methyl]-2-methyl-[1,3]thiazolo[3,2-b][1,2,4]triazol-6-ol is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H21Cl2N4OS+
assistant