You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
Provide the molecular formula for the IUPAC named substance (2R)-2-amino-N-[(2S)-6-azaspiro[2.5]octan-2-yl]-2-phenyl-N-(thiophen-3-ylmethyl)acetamide .
user
C20H25N3OS
assistant