You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Please write the molecular formula of the molecule 6-(2-methylpropyl)-9,19-dioxapentacyclo[10.8.0.02,11.03,8.013,18]icosa-3(8),4,6,13,15,17-hexaene-10,20-dione .
user
C22H20O4
assistant