You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named methyl-methylidene-[[methyl(methylidene)phosphaniumyl]-[3-(4-methylpiperazin-1-yl)azetidin-1-yl]methyl]phosphanium by IUPAC nomenclature, provide its molecular formula.
user
C13H27N3P2+2
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