You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule (1S,2S,3S,6S,8S,11S,15S,18S)-3,18-dimethoxy-11-methyl-10,13-dioxo-9,12-diazatricyclo[13.3.1.12,6]icosane-8-carboxylic acid .
user
C22H36N2O6
assistant