You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(1-pyrido[2,3-d]pyrimidin-4-ylpyrrolidin-2-yl)methyl]-7,8-dihydro-5H-pyrano[4,3-c]pyridazin-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H20N6O2
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