Which O2 Sensor is the B2, S1. And is it upstream or downstream? on 2003 Toyota Solara

Toyota diagnosis as to the reason my check engine light is on. B2-S1 O2 Sensor is bad..

Asked by for the 2003 Toyota Solara
bank 2 is the side closest to the front of the car.sensor 1 is the upstream or pre-cat.
Thank you for the information and your time ..
1 more answer , 2 more comments
that would be an upstream, sensor is located in or near the exhaust manifold, would be a better option to replace both bank 1 and bank 2 sensors at same time..
Thank you, I will follow your advice to replace both sensors..
NO problem