You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
ethyl 2,6-dimethyl-5-(6-phenyl-[1,2,4]triazolo[3,4-b][1,3,4]thiadiazol-3-yl)pyridine-3-carboxylate is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H17N5O2S
assistant