Rotating the camera to left or right using the scroll wheel

Hello, I am trying to rotate my camera using the scroll wheel.
What I'm saying is: The player press the mouse wheel and move to the left or to the right, so, the camera will rotate to the selected side.

How can I do this?

PS: The scroll wheel needs to be pressed to be able to spin.

 

Do you have the code to rotate your camera already set up? If so, all you need to do is enclose it in:
if (Input.GetMouseButton(2))
{
//rotation code goes here
}

 

I have the following code to left:

Code (csharp):

1. if (Input.GetMouseButton(2)  Input.GetAxis("Mouse X") < 0)
2.         {
3.             transform.Rotate(Vector3.up * 1.8f, Space.World);
4.         }

Do you know how to get a smooth rotation?