You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[(1R)-1-(1-benzofuran-2-yl)ethyl]-3-[(4S)-6-fluoro-3,4-dihydro-2H-thiochromen-4-yl]-1-methylurea into its molecular formula.
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C21H21FN2O2S
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