You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[4-[[(5S,8aS)-7-[(2-amino-1,3-benzothiazol-4-yl)methyl]-1-[methylcarbamoyl(prop-2-ynyl)amino]-3,6-dioxo-2,5,8,8a-tetrahydroimidazo[1,2-a]pyrazin-5-yl]methyl]phenyl]formamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C27H28N8O4S
assistant