You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6aR)-6,6-difluoro-1-hydroxy-3-pentyl-7,8,10,10a-tetrahydro-6aH-benzo[c]chromen-9-one The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H22F2O3
assistant