You are a chemist. Please follow the instructions to convert the structure to the corresponding name.
system
What is the molecular formula of the molecule 7-methoxy-5-pyridin-2-yl-2-thiophen-2-yl-5,10b-dihydro-1H-pyrazolo[1,5-c][1,3]benzoxazine ?
user
C20H17N3O2S
assistant