You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(2-phenylethyl)-2,4-dihydro-1H-pyridazino[6,1-c][1,4]oxazin-3-one;hydrochloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H17ClN2O2
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