You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named (2R)-2-amino-3-[[(3Z)-3-(carboxymethylidene)-1-[1-(2-chlorophenyl)-2-cyclopropyl-2-oxoethyl]piperidin-4-yl]disulfanyl]propanoic acid by IUPAC nomenclature, provide its molecular formula.
user
C21H25ClN2O5S2
assistant