You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
6,9,16,19-tetramethylpentacyclo[12.6.2.24,11.05,10.015,20]tetracosa-1(21),4(24),5,7,9,11(23),14(22),15,17,19-decaene The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H28
assistant