You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Can you give the molecular formula of the molecule 1-(5,6-difluoro-3a,7a-dihydro-1H-indol-7-yl)-2,4-dimethylidene-5,6,7,8-tetrahydro-4aH-pyrido[1,2-b]pyridazine ?
user
C18H21F2N3
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