You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-chloro-4-[5-[[4-[3-(dimethylamino)propyl]piperazin-1-yl]methyl]furan-2-yl]phenol by IUPAC nomenclature, provide its molecular formula.
user
C20H28ClN3O2
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