How to set maximum distance for a player going left and right?

I used this script in a project a year or so ago. Ignore the stuff you don't need but here. It assumes you want to kind of "switch lanes" left and right. Like an infinite runner maybe.`public class LaneSW : $$anonymous$$onoBehaviour {

 public AudioSource tickSource;
 public float speed = 6.0F;
 public float jumpSpeed = 8.0F;
 public float gravity = 20.0F;
 private Vector3 moveDirection = Vector3.zero;

 public int laneNumber = 0;
 public int lanesCount = 4;
 bool didChangeLastFrame = false;
 public float laneDistance = 2;
 public float firstLaneXPos = 0;
 public float deadZone = 0.1f;
 public float sideSpeed = 5;

 void Start() 
 {
     tickSource = GetComponent<AudioSource> ();
 }

 void Update() 
 {
     //Access the objects Character Controller
     CharacterController controller = GetComponent<CharacterController>();

     float input = Input.GetAxis("Horizontal");
     //$$anonymous$$ake sure the object is grounded before doing the math for lane changes
     if (controller.isGrounded)
     if($$anonymous$$athf.Abs(input) > deadZone) {
         if(!didChangeLastFrame) {
             didChangeLastFrame = true; //Prevent overshooting lanes
             laneNumber += $$anonymous$$athf.RoundToInt($$anonymous$$athf.Sign(input));
             if(laneNumber < 0) laneNumber = 0;
             else if(laneNumber >= lanesCount) laneNumber = lanesCount - 1;
         }
     }
     else 
     {
         didChangeLastFrame = false; 

         moveDirection = new Vector3(0, 0, Input.GetAxis("Vertical"));
         moveDirection = transform.TransformDirection(moveDirection);
         moveDirection *= speed;
         if (Input.GetButton("Jump"))
             moveDirection.y = jumpSpeed;

     }
     Vector3 pos = transform.position;
     pos.x = $$anonymous$$athf.Lerp(pos.x, firstLaneXPos + laneDistance * laneNumber, Time.deltaTime * sideSpeed);
     transform.position = pos;

     moveDirection.y -= gravity * Time.deltaTime;        
     controller.$$anonymous$$ove (moveDirection * Time.deltaTime);
 }


 void OnTriggerEnter(Collider other) 
 {
     if (other.gameObject.CompareTag ("Pick Up"))
     {
         tickSource.Play ();

         other.gameObject.SetActive (false);
     }
 }
     

     

} `