You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[[2-[(2S,5R)-2-[4-(difluoromethoxy)phenyl]-5-methylpiperidin-1-yl]-2-oxoacetyl]amino]pyridine-3-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H22F2N4O4
assistant