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 (4S)-4-(ethylamino)-1-[3-[(1S)-1-[3-(methylamino)thiophen-2-yl]propoxy]phenyl]azepan-2-one is given. What is its corresponding molecular formula?
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C22H31N3O2S
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