You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Convert the IUPAC name of a molecule ethyl (4R)-6-[(4-acetylpiperazin-1-yl)methyl]-4-(3-fluorophenyl)-2-oxo-3,4-dihydro-1H-pyrimidine-5-carboxylate into molecular formula.
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C20H25FN4O4
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