You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2-chloro-5-sulfanylphenyl)-(1-methyl-2,3,4,4a,5,7,8,8a-octahydro-1,6-naphthyridin-6-yl)methanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H21ClN2OS
assistant