You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2E,4E,7R,8E,12R,13R)-7,13-dihydroxy-4,8,12-trimethyltetradeca-2,4,8-trienoic acid by IUPAC nomenclature, provide its molecular formula.
user
C17H28O4
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