You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Translate the chemical IUPAC name 2-(2-chloro-4-fluorophenoxy)-N-(7,8,9,10-tetrahydro-6H-azepino[1,2-a]benzimidazol-3-yl)acetamide into its molecular formula.
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C20H19ClFN3O2
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