You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (4R,6R,9Z,11S,13E,15S)-4,9,13,18-tetramethyl-5,16-dioxatricyclo[13.3.0.04,6]octadeca-1(18),9,13-trien-11-ol by IUPAC nomenclature, provide its molecular formula.
user
C20H30O3
assistant