You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[(7R,9S)-7-(4-chlorophenyl)-4,5,13-trimethyl-11-oxa-3-thia-8,12-diazatricyclo[8.3.0.02,6]trideca-1(10),2(6),4,12-tetraen-9-yl]acetamide into its molecular formula.
user
C20H20ClN3O2S
assistant