You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5R)-5-(4-methoxyphenyl)-7-methyl-5,8-dihydro-[1,2,4]triazolo[4,3-a]pyrimidine is the IUPAC name of a molecule. Please give its molecular formula.
user
C13H14N4O
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