You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2R,4R)-4-phenyl-5-oxa-6,16-diazatetracyclo[7.7.0.02,6.010,15]hexadeca-1(9),10,12,14-tetraene by IUPAC nomenclature, provide its molecular formula.
user
C19H18N2O
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