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 (1S,2S,4R,5R,9S,10R,13S)-2-hydroxy-5,9,13-trimethyl-14-oxotetracyclo[11.2.1.01,10.04,9]hexadecane-5-carboxylic acid ?
user
C20H30O4
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