You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance 2-(4-cyclopropyl-4-methyl-2,5-dioxoimidazolidin-1-yl)-N-(2,3-dihydro-1H-inden-5-yl)acetamide .
user
C18H21N3O3
assistant