You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(4-ethylphenyl)-5-(1-methylpyrazol-4-yl)-1,1-dioxo-4H-1lambda6,2,4-benzothiadiazin-3-amine by IUPAC nomenclature, provide its molecular formula.
user
C19H19N5O2S
assistant