You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule [4-(6-imidazol-1-ylpyridazin-3-yl)piperazin-1-yl]-(4-methyl-3-nitrophenyl)methanone into molecular formula.
user
C19H19N7O3
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