You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-chloro-4,5-difluoro-N-methyl-N-[1-[4-(1,2,4-triazol-1-yl)phenyl]ethyl]benzamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H15ClF2N4O
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