void Awake()
 {
     if (instance == null) {
         instance = this;
         DontDestroyOnLoad(gameObject);
     } else {
         Destroy (gameObject);
     }
 }
 void Awake()
 {
     if (instance == null)
     {
         instance = this;
         DontDestroyOnLoad(gameObject);
     }
     else
     {
         Destroy(gameObject);
     }
 }