You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(7R)-N-(2,4-dimethylphenyl)-5-methyl-7-(5-methylfuran-2-yl)-4,7-dihydro-[1,2,4]triazolo[1,5-a]pyrimidine-6-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
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C20H21N5O2
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