You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 3-methyl-3-(3-methylbut-3-enyl)-2,5-diphenyl-2,5-bis(selanylidene)-1,2lambda5,5lambda5-selenadiphospholane .
user
C20H24P2Se3
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