You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule (1R,9S,12R)-12-(4-fluorophenyl)sulfonyl-5-methoxy-9,10-dimethyl-8-oxa-10-azatricyclo[7.3.1.02,7]trideca-2(7),3,5-trien-11-one ?
user
C20H20FNO5S
assistant