You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-methyl-3-[3-(morpholine-4-carbonyl)phenyl]-7-pyridin-4-ylthieno[2,3-d]pyridazin-4-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H20N4O3S
assistant