You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 2-phenyl-4-(4-phenylphenyl)-6-spiro[benzo[b]fluorene-11,9'-thioxanthene]-8-yl-1,3,5-triazine into molecular formula.
user
C50H31N3S
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