You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(6aS,10aR)-6,6,9-trimethyl-3-methylsulfanyl-2,5,6a,7,8,10a-hexahydrobenzo[f]quinazolin-1-one is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H22N2OS
assistant