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 N-[2-(3-chlorophenyl)ethyl]-2-[[(1S)-1-(2,4-difluorophenyl)ethyl]amino]acetamide is given. What is its corresponding molecular formula?
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C18H19ClF2N2O
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