You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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For the molecule named (E,3R)-2-[2-(4-aminopiperidin-1-yl)ethyl]-1-N'-ethynyl-3-N'-[(5E,7Z)-9-methylidene-3,4-dihydro-2H-oxonin-6-yl]prop-1-ene-1,1,3,3-tetramine by IUPAC nomenclature, provide its molecular formula.
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C21H34N6O
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