You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Can you give the molecular formula of the molecule 1-[(7-chloro-4-oxopyrido[1,2-a]pyrimidin-2-yl)methyl]-N,N-diethyl-6-oxopyridine-3-sulfonamide ?
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C18H19ClN4O4S
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