You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-[[4-(diethylsulfamoyl)phenyl]methyl]-[1,2,4]triazolo[4,3-a]pyridine-6-carboxamide by IUPAC nomenclature, provide its molecular formula.
user
C18H21N5O3S
assistant