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 6-(3,5-difluorophenyl)-8-ethoxy-N-methyl-2-pyrimidin-4-ylquinazolin-4-amine is given. What is its corresponding molecular formula?
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C21H17F2N5O
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