You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
[2-oxo-2-[[(2S)-2-phenylpropyl]amino]ethyl]-[(R)-phenyl(thiophen-2-yl)methyl]azanium is the IUPAC name of a molecule. Please give its molecular formula.
user
C22H25N2OS+
assistant