You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Under IUPAC nomenclature, a molecule named 2-(2,4-dichlorophenyl)-5-pyrazin-2-yl-1H-pyrazolo[1,5-a]pyrimidin-7-one is given. What is its corresponding molecular formula?
user
C16H9Cl2N5O
assistant