You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-benzyl-7-(4-bromo-3-chlorobenzoyl)-2-(4-methylsulfonylphenyl)-3-oxo-6,8-dihydro-5H-imidazo[1,5-a]pyrazine-1-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C28H24BrClN4O5S
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