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 N'-[2-(2,3-dihydroindol-1-yl)-2-oxoethyl]-N-ethyl-2-azaspiro[4.4]nonane-2-carboximidamide;hydroiodide .
user
C21H31IN4O
assistant