You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[4-[1-(4-bromophenyl)-2,5-dioxopyrrolidin-3-yl]piperazin-4-ium-1-yl]phenolate into its molecular formula.
user
C20H20BrN3O3
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