You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
3-[7-chloro-5-(2-fluorophenyl)-2-methylidene-3H-1,4-benzodiazepin-1-yl]propanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H16ClFN2O2
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