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 3-butyl-8-chloro-1-[3-[5-[(4-chlorophenyl)methyl]tetrazol-2-yl]propyl]-7H-purine-2,6-dione ?
user
C20H22Cl2N8O2
assistant