You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 4-[(S)-(3-fluorophenyl)-(6-hydroxy-[1,3]thiazolo[3,2-b][1,2,4]triazol-5-yl)methyl]piperazin-4-ium-1-carboxylate The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H21FN5O3S+
assistant