You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
2-methyl-2-[2-oxo-2-[[2-(2-oxopyrrolidin-1-yl)acetyl]amino]ethyl]sulfanylpropanoic acid is the IUPAC name of a molecule. Please give its molecular formula.
user
C12H18N2O5S
assistant