You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(3-fluorophenyl)-2-methyl-2-(6-oxo-7,8,9,10-tetrahydro-6aH-phenanthridin-3-yl)propanenitrile The above is the IUPAC name of a molecule. Write its molecular formula.
user
C23H21FN2O
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