You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
5-[(4-chlorophenyl)diazenyl]-2-hydroxy-4-methyl-6-oxo-1-propylpyridine-3-carbonitrile The above is the IUPAC name of a molecule. Write its molecular formula.
user
C16H15ClN4O2
assistant