You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
4-(4-chlorophenyl)-N-[[6-(trifluoromethyl)imidazo[1,2-a]pyridin-2-yl]methyl]butanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H17ClF3N3O
assistant