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 2-[4-(2-fluorophenyl)-4-methyl-2,5-dioxoimidazolidin-1-yl]-N-(2-oxo-2-pyrrolidin-1-ylethyl)acetamide .
user
C18H21FN4O4
assistant