Mobile input is not working.

Hello guys ...i have a problem regarding mobile input . I have created a script for rolling a cube with arrow keys ...now i want to change it in drag system . But when i try to change it its not working .. i am using the unity only past month so i m not familiar with its settings.. I am showing you my whole script and the error one part....

THIS IS MY WHOLE SCRIPT....

public float rotationPeriod = 0.3f;
public float sideLength = 1f;

 bool isRotate = false;                    
 float directionX = 0;                    
 float directionZ = 0;                    
 
 Vector3 startPos;                        
 float rotationTime = 0;                    
 float radius;                            
 Quaternion fromRotation;                
 Quaternion toRotation;                    
 
 // Use this for initialization
 void Start () {
 
     
     radius = sideLength * Mathf.Sqrt (2f) / 2f;
 
 }
 
 // Update is called once per frame
 void Update () {
 
     float x = 0;
     float y = 0;
     
     
     x = Input.GetAxisRaw ("Horizontal");
     if (x == 0) {
         y = Input.GetAxisRaw ("Vertical");
     }
 
 
     if ((x != 0 || y != 0) && !isRotate) {
         directionX = y;                                                                
         directionZ = x;                                                                
         startPos = transform.position;                                                
         fromRotation = transform.rotation;                                            
         transform.Rotate (directionZ * 90, 0, directionX * 90, Space.World);    
         toRotation = transform.rotation;                                            
         transform.rotation = fromRotation;                                            
         rotationTime = 0;                                                            
         isRotate = true;                                                            
     }
 }
 
 void FixedUpdate() {
 
     if (isRotate) {
 
         rotationTime += Time.fixedDeltaTime;                                    
         float ratio = Mathf.Lerp(0, 1, rotationTime / rotationPeriod);            
 
         
         float thetaRad = Mathf.Lerp(0, Mathf.PI / 2f, ratio);                

         float distanceX = -directionX * radius * (Mathf.Cos (45f * Mathf.Deg2Rad) - Mathf.Cos (45f * Mathf.Deg2Rad + thetaRad));        

         float distanceY = radius * (Mathf.Sin(45f * Mathf.Deg2Rad + thetaRad) - Mathf.Sin (45f * Mathf.Deg2Rad));                        
         float distanceZ = directionZ * radius * (Mathf.Cos (45f * Mathf.Deg2Rad) - Mathf.Cos (45f * Mathf.Deg2Rad + thetaRad));            
         transform.position = new Vector3(startPos.x + distanceX, startPos.y + distanceY, startPos.z + distanceZ);                        
 
         
         transform.rotation = Quaternion.Lerp(fromRotation, toRotation,ratio);
         
         if (ratio == 1) {
             isRotate = false;
             directionX = 0;
             directionZ = 0;
             rotationTime = 0;
         }
     }
 }

}

THIS IS ERRORED ONE PART ---

void Update () {

     float x = 0;
     float y = 0;
     
     
     x = Input.GetAxisRaw ("Horizontal");
     if (x == 0) {
         y = Input.GetAxisRaw ("Vertical");
     }
 
 
     if ((x != 0 || y != 0) && !isRotate) {
         directionX = y;                                                                
         directionZ = x;                                                                
         startPos = transform.position;                                                
         fromRotation = transform.rotation;                                            
         transform.Rotate (directionZ * 90, 0, directionX * 90, Space.World);    
         toRotation = transform.rotation;                                            
         transform.rotation = fromRotation;                                            
         rotationTime = 0;                                                            
         isRotate = true;                                                            
     }
 }

Check my mistake plzz ...