You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-[[(2S,3S,4S,5S)-3-[2-(difluoromethoxy)-3,4-difluorophenyl]-4,5-dimethyl-5-(trifluoromethyl)oxolane-2-carbonyl]amino]-1-hydroxypyridin-1-ium-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H19F7N3O5+
assistant