You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the compound with this IUPAC name 7-chloro-5-methyl-4-oxo-1-(4-pyridin-3-yl-1,3-thiazol-2-yl)-1,8-naphthyridine-3-carboxylic acid ?
user
C18H11ClN4O3S
assistant