You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule identified by (1R,2S,8S,9S)-8-[(3-methoxyphenyl)methyl]-11-methylsulfonyl-7,11-diazatricyclo[7.3.1.02,7]tridecane ?
user
C20H30N2O3S
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