You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-methyl-N-[2-[5-[1-(4-methylpyridine-3-carbonyl)azetidin-3-yl]-1,2,4-oxadiazol-3-yl]ethyl]oxane-4-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H27N5O4
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