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 (2S)-2-[(3aR,6aS)-2,5-dioxo-3,3a,6,6a-tetrahydro-1H-imidazo[4,5-d]imidazol-4-yl]butanoic acid .
user
C8H12N4O4
assistant