You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6-[(7-bromo-6-hydroxy-3,4-dihydro-1H-isoquinolin-2-yl)methyl]-4H-1,4-benzoxazin-3-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H17BrN2O3
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