You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Under IUPAC nomenclature, a molecule named 4-ethoxy-N-[(1S,2R)-1-(4-methylpiperazine-1,4-diium-1-yl)-1-thiophen-2-ylpropan-2-yl]benzamide is given. What is its corresponding molecular formula?
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C21H31N3O2S+2
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