You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-butyl-3-[2-(5-butylcyclopenta-1,4-dien-1-yl)ethyl]cyclopenta-1,3-diene;titanium(4+);dichloride is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H28Cl2Ti
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