You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name N-[3-(1,1-dioxothiazinan-2-yl)phenyl]-2-(3-oxo-6,7,8,9-tetrahydro-5H-cyclohepta[c]pyridazin-2-yl)acetamide into its molecular formula.
user
C21H26N4O4S
assistant