You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named thiophen-3-ylmethyl 2-(2H-benzotriazole-5-carbonyl)-2,7-diazaspiro[3.5]nonane-7-carboxylate by IUPAC nomenclature, provide its molecular formula.
user
C20H21N5O3S
assistant