You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-methyl-2-[4-(6-methylpyridazin-3-yl)phenyl]-4-(2-pyrrolidin-1-ylethyl)-1,3-oxazole is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H24N4O
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