You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-(7-pyridin-2-yloxy-5-thia-2-azaspiro[3.4]octan-2-yl)-2-thiophen-3-ylethanone The above is the IUPAC name of a molecule. Write its molecular formula.
user
C17H18N2O2S2
assistant