You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[(5aS,9aR)-4-pyrimidin-2-yl-2,3,5,5a,6,7,9,9a-octahydropyrido[4,3-f][1,4]oxazepin-8-yl]-pyridazin-4-ylmethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C17H20N6O2
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