You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2,3-dimethylbutane-1,4-dione;3,4-dimethylhexane-2,5-dione;3-methylhexane;yttrium The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H38O4Y-2
assistant