You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[(3-methyl-2-oxobutyl)-[3-[(3-methyl-2-oxobutyl)-(2-oxopropyl)amino]propyl]amino]acetamide The above is the IUPAC name of a molecule. Write its molecular formula.
user
C18H33N3O4
assistant