You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
N-[[4-(4-hydroxybut-1-ynyl)thiophen-2-yl]methyl]-N,3-dimethylimidazole-4-carboxamide is the IUPAC name of a molecule. Please give its molecular formula.
user
C15H17N3O2S
assistant