Cam giving problem on rotation and pan

Here is the script which is giving problem literally. I tried but cant find where the problem occur. please help me to do this.

 //In a file MaxCamera.cs
 
 using UnityEngine;
 using System.Collections; 
 
 public class MaxCamera : MonoBehaviour{
 
     public Transform target; 
     public Vector3 targetOffset;
     public float distance = 5.0f;
     public float maxDistance = 20;
     public float minDistance = .6f; 
     public float xSpeed = 200.0f;
     public float ySpeed = 200.0f; 
     public int yMinLimit = -80;
     public int yMaxLimit = 80; 
     public int zoomRate = 40;
     public float panSpeed = 0.3f; 
     public float zoomDampening = 5.0f; 
     private float xDeg = 0.0f;
     private float yDeg = 0.0f;
     private float currentDistance;
     private float desiredDistance; 
     
     private float x, y;
     
     //reset image
     public GUIStyle reset;
 
     void Start()
     {
         x = y = 0;
         
         //make the faul screen false at the start
         Screen.fullScreen = false;
         
         Vector3 angles = transform.eulerAngles;
        // xDeg = angles.x;
         //yDeg = angles.y;
         currentDistance = distance;
         desiredDistance = distance;
         
         gameObject.transform.position = new Vector3(10.225f, 1.74f, -29.35f);
     }
     
     void Update()
     {        
         if(Input.GetKeyDown(KeyCode.F))
             Screen.fullScreen = !Screen.fullScreen;
     }
     /** 
      * Camera logic on LateUpdate to only update after all character movement logic has been handled. 
      */
 
     void LateUpdate()
     {
         //if(Input.mousePosition.x > 48 && Input.mousePosition.x < 511 && Input.mousePosition.y > 48 && Input.mousePosition.y < 620)
         {
             
             // Don't do anything if target is not defined 
     
             if (!target)
                 return;
     
             // If Control and Alt and Middle button? ZOOM!
 //            if (Input.GetMouseButton(2) && Input.GetKey(KeyCode.LeftAlt) && Input.GetKey(KeyCode.LeftControl))
 //            {
 //                desiredDistance -= Input.GetAxis("Mouse Y") * Time.deltaTime * zoomRate*0.125f * Mathf.Abs(desiredDistance);
 //            }
             
         if(Input.GetMouseButton(0))
             {
                 x -= Input.GetAxis("Mouse Y")* 10 * 0.02f;
                 y +=Input.GetAxis("Mouse X") * 10 * 0.02f;
                 
                 //target.transform.Rotate(0, -Input.GetAxis("Mouse X") * 10,0, Space.World);
             }            
             
             
             // If middle mouse and left alt are selected? ORBIT
             //else if (Input.GetMouseButton(2) && Input.GetKey(KeyCode.LeftAlt))
             else if (Input.GetMouseButton(1))
             {
                 xDeg += Input.GetAxis("Mouse X") * xSpeed * 0.02f;
                 yDeg -= Input.GetAxis("Mouse Y") * ySpeed * 0.02f;
             }
             
             // otherwise if middle mouse is selected, we pan by way of transforming the target in screenspace
             else if (Input.GetMouseButton(2))
             {
                 //grab the rotation of the camera
                                 
                 if(targetOffset.y <= 25)
                 {
                      targetOffset.x -= (transform.right * Input.GetAxis("Mouse X") * 0.00002f).x;
                        targetOffset.y -= (Vector3.up * Input.GetAxis("Mouse Y") * 0.00002f).y;
                 }                
                 else
                     targetOffset.y = 24.5f;
             }
             
               //Clamp the vertical axis for the orbit
             yDeg = ClampAngle(yDeg, yMinLimit, yMaxLimit);
                  
             // set camera rotation 
             Quaternion rotation = Quaternion.Euler(x, y, 0); 
             
             // affect the desired Zoom distance if we roll the scrollwheel
             desiredDistance -= Input.GetAxis("Mouse ScrollWheel") * Time.deltaTime * zoomRate * Mathf.Abs(desiredDistance);
     
             //clamp the zoom min/max
             desiredDistance = Mathf.Clamp(desiredDistance, minDistance, maxDistance); 
     
           
     
             // For smoothing of the zoom, lerp distance
             currentDistance = Mathf.Lerp(currentDistance, desiredDistance, Time.deltaTime * zoomDampening); 
     
             // keep within legal limits
             currentDistance = Mathf.Clamp(currentDistance, minDistance, maxDistance);
      
     
             // calculate position based on the new currentDistance 
             Vector3 position = target.position + (rotation * Vector3.forward * currentDistance + targetOffset);
             //Vector3 position = transform.position;
             transform.rotation = rotation;
             transform.position = position;
         }
     }
     
     private static float ClampAngle(float angle, float min, float max)
     {
         if (angle < -360)
             angle += 360;
         
         if (angle > 360)
             angle -= 360;
 
         return Mathf.Clamp(angle, min, max);
     }
     
     void OnGUI()
     {
         //for4:3 resolution
         //if(GUI.Button(new Rect(7, Screen.width / 2 + 133, 30, 25),"",reset))
         if(GUI.Button(new Rect(10, Screen.width / 2 + 138, 30, 25),"",reset))
         {
             target.transform.rotation = Quaternion.Euler(0, 0, 0);
         }    
         
         //print(Input.mousePosition.x + " "+ Input.mousePosition.y);
     }
 
 }