You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (3Z,4aS,5S)-3-[(4-fluorophenyl)methylidene]-5-hydroxy-1,4a-dimethyl-5,6,7,8-tetrahydro-4H-naphthalen-2-one .
user
C19H21FO2
assistant