How do I make this Camera movement happen when I right click?

This allows me to rotate and move the camera when I move my mouse fine but I want to make it move only when I right click and move around the mouse

using System.Collections;
using System.Collections.Generic;
using UnityEngine;

public class TestCam : MonoBehaviour {

	//All the variables used in this class(Look below to see what they do. :D   )
	private const float Y_ANGLE_MIN = 0.0f;
	private const float Y_ANGLE_MAX = 50.0f;
	private const float DISTANCE_MAX = 5.0f;
	private const float DISTANCE_MIN = 0.1f;
	private const float TRANS_MIN = 1.0f;
	private const float TRANS_MAX = 2.0f;

	public Transform lookAt;
	public Transform camTransform;
	public GameObject player;

	private Camera cam;

	public float distance = 5.0f;
	private float currentX = 0.0f;
	private float currentY = 0.0f;
	private float sensitivityX = 4.0f;
	private float sensitivityY = 1.0f;
	private float trandis;

	public Vector3 height = new Vector3(0, 0, 0);

	private bool below = false;

	private void Start()
	{

		//Makes camTransform a transform. :)

		camTransform = transform;
		//Sets variable cam value to the main camera
		cam = Camera.main;

	}

	private void Update()
	{

		//Makes the camera move by looking at the axis of the mouse(Also multiplied by the seisitivity.)

			currentX += Input.GetAxis ("Mouse X") * sensitivityX;
			currentY += Input.GetAxis ("Mouse Y") * sensitivityY;

		//Limits the Y variable
		currentY = Mathf.Clamp(currentY, Y_ANGLE_MIN, Y_ANGLE_MAX);

		//Thiago Laranja's scrollwheel implemetation.
		if (Input.GetAxis("Mouse ScrollWheel") > 0) { distance += 0.2f; }
		if (Input.GetAxis("Mouse ScrollWheel") < 0) { distance -= 0.2f; }

		//Makes sure that these variables never go over the max and be les than the min. :)
		distance = Mathf.Clamp(distance, DISTANCE_MIN, DISTANCE_MAX);
		trandis = Mathf.Clamp(distance, TRANS_MIN, TRANS_MAX) - 1;

		//Sets players transparency(Make sure that player materials rendering mode has set to transparent or other mode that supports transparency).
		player.GetComponent<Renderer>().material.color = new Color(player.GetComponent<Renderer>().material.color.r, player.GetComponent<Renderer>().material.color.g, player.GetComponent<Renderer>().material.color.b,trandis);

		//Disables the object from rendering if your're at distance 0.8.
		if (distance <= 0.8f) { player.GetComponent<Renderer>().enabled = false; }
		if (distance > 0.8f) { player.GetComponent<Renderer>().enabled = true; }

		//If close enough to the character sinp into distance of 0.1(If distance is 0 the camera cant be rotated.)
		if (distance <= 0.8f && below == false) { distance = 0.1f; below = true; }
		if (distance >= 0.8f && below == true) { below = false; }
		
	}
	private void LateUpdate()
	{

		//Subtracts hte distance from Z coordinate
		Vector3 dir = new Vector3(0, 0, -distance);

		//Creates an quaternion for rotation(too bad that we cannot use Vector3. :D   )
		Quaternion rotation = Quaternion.Euler(currentY, currentX, 0);

		//Sets the cameras position and makes it look at player.
		camTransform.position = lookAt.position + height + rotation * dir;
		camTransform.LookAt(lookAt.position + height);

	}

}

Add this code into your Update() method

        if (!Input.GetMouseButton(1))
            return;

or if you don’t want to return the Update change Update with this :

         //Makes the camera move by looking at the axis of the mouse(Also multiplied by the seisitivity.)
 
if(Input.GetMouseButton(1)){
             currentX += Input.GetAxis ("Mouse X") * sensitivityX;
             currentY += Input.GetAxis ("Mouse Y") * sensitivityY;
 
         //Limits the Y variable
         currentY = Mathf.Clamp(currentY, Y_ANGLE_MIN, Y_ANGLE_MAX);
 
         //Thiago Laranja's scrollwheel implemetation.
         if (Input.GetAxis("Mouse ScrollWheel") > 0) { distance += 0.2f; }
         if (Input.GetAxis("Mouse ScrollWheel") < 0) { distance -= 0.2f; }
 
         //Makes sure that these variables never go over the max and be les than the min. :)
         distance = Mathf.Clamp(distance, DISTANCE_MIN, DISTANCE_MAX);
         trandis = Mathf.Clamp(distance, TRANS_MIN, TRANS_MAX) - 1;
}
         //Sets players transparency(Make sure that player materials rendering mode has set to transparent or other mode that supports transparency).
         player.GetComponent<Renderer>().material.color = new Color(player.GetComponent<Renderer>().material.color.r, player.GetComponent<Renderer>().material.color.g, player.GetComponent<Renderer>().material.color.b,trandis);
 
         //Disables the object from rendering if your're at distance 0.8.
         if (distance <= 0.8f) { player.GetComponent<Renderer>().enabled = false; }
         if (distance > 0.8f) { player.GetComponent<Renderer>().enabled = true; }
 
         //If close enough to the character sinp into distance of 0.1(If distance is 0 the camera cant be rotated.)
         if (distance <= 0.8f && below == false) { distance = 0.1f; below = true; }
         if (distance >= 0.8f && below == true) { below = false; }