You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Translate the chemical IUPAC name 1-[2-(diethylamino)ethyl]-3-[2-(5-methyl-5-prop-1-en-2-ylcyclohepta-1,3,6-trien-1-yl)propan-2-yl]urea into its molecular formula.
user
C21H35N3O
assistant