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 [2-[[(1S)-1-(2,4-dichlorophenyl)ethyl]amino]-2-oxoethyl]-[(2-fluorophenyl)methyl]-methylazanium is given. What is its corresponding molecular formula?
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C18H20Cl2FN2O+
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