You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 3-[(3-fluoro-4-pyridin-3-yloxyphenyl)methyl]-1-methyl-1-(oxan-2-ylmethyl)urea by IUPAC nomenclature, provide its molecular formula.
user
C20H24FN3O3
assistant