You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R,3R,4aR,10bR)-5,5-dimethyl-7-phenyl-2-propyl-3,4,4a,10b-tetrahydro-2H-pyrano[3,2-c]chromene-3-carboxylic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C24H28O4
assistant