You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[4-[(6aR,7R,11aR)-4-(2-fluorophenyl)-7,11a-dimethyl-6,6a,7,11-tetrahydro-5H-[1,2]benzoxazolo[6,5-h]quinazolin-2-yl]pyridin-2-yl]methyl methanesulfonate is the IUPAC name of a molecule. Please give its molecular formula.
user
C28H27FN4O4S
assistant