You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[2-[[5-chloro-2-[(4,5-dimethoxypyridin-3-yl)amino]pyrimidin-4-yl]amino]-5-methoxyphenyl]thiohydroxylamine is the IUPAC name of a molecule. Please give its molecular formula.
user
C18H19ClN6O3S
assistant