You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(1R,4S,5S)-2,2,5,7-tetramethylspiro[1,4-dihydroindene-6,1'-cyclopropane]-1,4,5-triol The above is the IUPAC name of a molecule. Write its molecular formula.
user
C15H22O3
assistant