You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (E)-1-(2,3,4a,5,6,7,8,8a-octahydrobenzo[b][1,4]oxazin-4-yl)-3-(2-fluorophenyl)-2-methylprop-2-en-1-one ?
user
C18H22FNO2
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