You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-(2,6-dioxo-1,3-diazinan-4-yl)phenyl]-1,2,5-trimethylpyrrole-3-carboxamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H20N4O3
assistant