You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(2R)-2-(4-chlorophenyl)-3-methyl-N-(4-pyridin-3-yl-1,3-thiazol-2-yl)butanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C19H18ClN3OS
assistant