You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
(4aS,12aR)-8-[[butyl(methyl)amino]methyl]-1,10,11,12a-tetrahydroxy-7-methoxy-3,12-dioxo-4a,5,5a,6-tetrahydro-4H-tetracene-2-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C26H32N2O8
assistant