You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-[[2-(4-bromo-2-chlorophenoxy)acetyl]-[(4-chlorophenyl)methyl]amino]-N-tert-butylpropanamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H25BrCl2N2O3
assistant