You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
For the molecule named 2-amino-2-methyl-4-[5-[4-(4-methylphenoxy)but-1-ynyl]thiophen-2-yl]butan-1-ol by IUPAC nomenclature, provide its molecular formula.
user
C20H25NO2S
assistant