Where are the oxygen sensors located?

Hello,

This vehicle has four oxygen sensors.
Two of them are located before the catalytic converter, after the exhaust manifold.
The other two are located after the catalytic converter on the exhaust pipe.

https://www.2carpros.com/articles/how-to-replace-an-oxygen-sensor

I have attached diagrams below for your reference.

Let me know of any questions.
Thank you.