You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[4-[[3,5-bis[[4,7,10-tris(carboxymethyl)-1,4,7,10-tetrazacyclododec-1-yl]methyl]phenyl]methyl]-7,10-bis(carboxymethyl)-1,4,7,10-tetrazacyclododec-1-yl]acetic acid by IUPAC nomenclature, provide its molecular formula.
user
C51H84N12O18
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