You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
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Please write the molecular formula of the molecule 3-(3-chloro-4-fluorophenyl)-1-[(1S)-8,9-difluoro-4,6-dioxo-2,5-dihydro-1H-pyrano[3,4-c]isoquinolin-1-yl]-1-methylurea .
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C20H13ClF3N3O4
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