You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[1-[3-[(3-fluoropyridin-4-yl)amino]propyl]-6-methyl-2-oxopyridin-3-yl]-1-phenylmethanesulfonamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C21H23FN4O3S
assistant