You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 2-[2-(4-fluorophenyl)ethyl]-6-[(2R)-1-propylsulfonylpyrrolidin-2-yl]pyridine-3-carboxylic acid into its molecular formula.
user
C21H25FN2O4S
assistant