How to set the boundaries of the camera movement along the boundaries of the background (sprite)?

Question

Unity

Hello everybody!
I'm making a 2d game, with the ability to move the camera with swipes. I set the boundaries through Mathf.Clamp () so that the camera does not go beyond the sprite (background). But with a different screen resolution, the camera narrows and the specified boundaries become insufficient. A collider hangs on the background sprite, because clicks need to be read. I tried to take the size of the collider, but nothing good came of it.
I would like to know how you can get the correct borders for the camera at any screen resolution. It can be calculated through some formulas, depending on the resolution and size ..