You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named N-(2,4-dimethylphenyl)-2-[[(2S)-oxolan-2-yl]methyl-(thiophen-2-ylmethyl)amino]acetamide by IUPAC nomenclature, provide its molecular formula.
user
C20H26N2O2S
assistant