You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[6-[(2,4-dichlorophenyl)methyl]-12,12-dimethyl-3,5-dioxo-11-oxa-8-thia-4,6-diazatricyclo[7.4.0.02,7]trideca-1(9),2(7)-dien-4-yl]acetic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H18Cl2N2O5S
assistant