You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
tert-butyl 2-[[4-[2-[(5-bromopyrazin-2-yl)amino]ethyl]-1,3-thiazol-2-yl]sulfanyl]-2-methylpropanoate is the IUPAC name of a molecule. Please give its molecular formula.
user
C17H23BrN4O2S2
assistant