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 3-[[2-(3-methylbutanoyl)-3,4-dihydro-1H-isoquinoline-3-carbonyl]amino]cyclobutane-1-carboxylic acid is given. What is its corresponding molecular formula?
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C20H26N2O4
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