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 2-(2-methyl-4-oxo-5,6,7,8-tetrahydroquinazolin-3-yl)-N-(3-methylphenyl)acetamide is given. What is its corresponding molecular formula?
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C18H21N3O2
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