You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name (5Z)-3-ethyl-5-[(2Z)-2-[3-ethyl-5-(trifluoromethyl)-1,3-benzothiazol-2-ylidene]ethylidene]-2-methylsulfanyl-1,3-thiazol-3-ium-4-one;iodide ?
user
C18H18F3IN2OS3
assistant