You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-(6-amino-1-butyl-2,4-dioxopyrimidin-5-yl)-2-(3-ethyl-2,4-dioxoquinazolin-1-yl)-N-methylacetamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C21H26N6O5
assistant