You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name (4R)-N-(4-chloro-2,5-dimethoxyphenyl)-2-methyl-4-(3-methylphenyl)-1,4-dihydropyrimido[1,2-a]benzimidazole-3-carboxamide into its molecular formula.
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C27H25ClN4O3
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