You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
7-(6-cyclopropylpyridin-3-yl)-3,6-difluoro-2,3-dihydro-1H-pyrrolo[1,2-a]benzimidazole The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H15F2N3
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