You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[1-[4-(dimethylamino)pyrimidin-2-yl]piperidin-4-yl]methyl]-6-pyridin-4-ylpyridazin-3-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H25N7O
assistant