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-[[4-(thiophene-2-carbonyl)piperazin-1-ium-1-yl]methyl]-2,3-dihydro-[1,4]dioxino[2,3-f]indole-7,8-dione .
user
C20H20N3O5S+
assistant