You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
1-[5-[2-[5-(5-hydroxypyridin-3-yl)-1H-pyrazolo[4,3-b]pyridin-3-yl]-1H-imidazo[4,5-b]pyridin-7-yl]thiophen-2-yl]ethanone is the IUPAC name of a molecule. Please give its molecular formula.
user
C23H15N7O2S
assistant