You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-(7-chloro-4-methyl-5-oxidoimidazo[1,5-a]quinoxalin-5-ium-3-yl)-5-(4-fluorophenyl)-1,2,4-oxadiazole is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H11ClFN5O2
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