You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,4aR,10bR)-2,5,5-trimethyl-3,4,4a,10b-tetrahydro-2H-pyrano[3,2-c]chromen-10-ol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H20O3
assistant