You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (3R,4S,5S,7R,9R,10S,11R,12R)-12-ethyl-4,10-dihydroxy-3,5,7,9,11-pentamethyl-oxacyclododecane-2,8-dione by IUPAC nomenclature, provide its molecular formula.
user
C18H32O5
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