You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(1-benzothiophen-3-ylmethyl)-N-methyl-3-(3-methyl-1,2,4-oxadiazol-5-yl)pyridin-2-amine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H16N4OS
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