You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-[(5-chloro-2,3-dihydro-1,4-benzodioxin-7-yl)methyl]-3-ethyl-6,8-dihydro-5H-[1,2,4]triazolo[4,3-a]pyrazine is the IUPAC name of a molecule. Please give its molecular formula.
user
C16H19ClN4O2
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