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 (3R,4S)-N-ethyl-N-[2-[(4-fluorophenyl)methylamino]-2-oxoethyl]-4-(1-methylpyrazol-4-yl)pyrrolidine-3-carboxamide;hydrochloride is given. What is its corresponding molecular formula?
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C20H27ClFN5O2
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