You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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2-[[2-[(5,5-dimethyl-1,3,2-dioxaphosphinan-2-yl)methyl]phenyl]methyl]-5,5-dimethyl-1,3,2-dioxaphosphinane is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H28O4P2
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