You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 4-[2-[methyl-[2-(4-sulfanylidenecyclohexa-1,5-dien-1-yl)oxypyridin-3-yl]amino]ethoxy]benzaldehyde .
user
C21H20N2O3S
assistant