You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 5-[5-(4-ethylpiperazin-1-yl)sulfonyl-2-(2-methoxyethoxy)pyridin-3-yl]-2,3-dimethyl-6H-pyrazolo[4,3-d]pyrimidin-7-one by IUPAC nomenclature, provide its molecular formula.
user
C21H29N7O5S
assistant