You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[3-([1,3]thiazolo[5,4-b]pyridin-2-yl)phenyl]-3-[4-(trifluoromethyl)phenyl]urea is the IUPAC name of a molecule. Please give its molecular formula.
user
C20H13F3N4OS
assistant