You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(5E)-1-(5-chloro-2-methylphenyl)-5-[(3,5-dibromo-2-prop-2-enoxyphenyl)methylidene]-1,3-diazinane-2,4,6-trione is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H15Br2ClN2O4
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