You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Convert the IUPAC name of a molecule 1-ethyl-2-[[4-(imidazol-1-ylmethyl)phenyl]methyl]-3-[3-(2-oxopyrrolidin-1-yl)propyl]guanidine into molecular formula.
user
C21H30N6O
assistant