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-[(3S)-3-ethylpyrrolidin-1-yl]-N-[3-methyl-4-(1-methylbenzimidazol-5-yl)oxyphenyl]pyrimido[5,4-d]pyrimidin-4-amine is given. What is its corresponding molecular formula?
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C27H28N8O
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