You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named tert-butyl N-[(1S,10R)-10-(5-ethynyl-2-fluorophenyl)-10-methyl-1-oxo-1lambda6-thia-2,7,9-triazabicyclo[5.4.0]undeca-1,8-dien-8-yl]carbamate by IUPAC nomenclature, provide its molecular formula.
user
C21H27FN4O3S
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