private void OnCollisionEnter2D(Collision2D collision)
 {
     // if balls enter this collison if it isn't last ball destroy it.
     // if it is last ball look health if player has health change ball position to start point.
     // if hasn't health finish game write point to the screen
     if (collision.gameObject.CompareTag("ball"))
     {
         GameObject[] balls;
         balls = GameObject.FindGameObjectsWithTag("ball");
         if (balls.Length == 1)
         {
             if (health > 1)
             {
                 health = health - 1;
                 play.CreateBall();
                 image2.SetActive(false);
                 sS.PlaySound(0);
                 Game.instance.StopSpeedChange();
             }
             else if (health <= 1)
             {
                 Time.timeScale = 0;
                 sS.PlaySound(0);
                 health -= 1;
                 cont_ads_button.enabled = true;
                 Game.instance.StopSpeedChange();
                 cont_ads_button.GetComponentInChildren <Text>().text = Lang.instance.text[14].text;
                 if (PlayerPrefs.GetInt("GameOverCount", 0) == 3)
                 {
                     GP_AdManager.instance.Display_InsterstitialAD();
                     PlayerPrefs.SetInt("GameOverCount", 0);
                 }
                 else
                 {
                     PlayerPrefs.SetInt("GameOverCount", PlayerPrefs.GetInt("GameOverCount", 0) + 1);
                 }
                 gameOver.SetActive(true);
             }
         }
         else
         {
             Destroy(collision.gameObject);
         }
     }
 }