You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-[[2-[[2-[(2-amino-3-sulfanylpropanoyl)amino]-3-sulfanylpropanoyl]amino]-3-phenylpropanoyl]amino]-5-(diaminomethylideneamino)pentanoic acid by IUPAC nomenclature, provide its molecular formula.
user
C21H33N7O5S2
assistant