You might know some pretty large perfect squares.  But what about the NEXT one?

Complete the `findNextSquare` method that finds the next integral perfect square after the one passed as a parameter.  Recall that an integral perfect square is an integer n such that sqrt(n) is also an integer.  

If the parameter is itself not a perfect square then `-1` should be returned.  You may assume the parameter is positive.


**Examples:**

```
findNextSquare(121) --> returns 144
findNextSquare(625) --> returns 676
findNextSquare(114) --> returns -1 since 114 is not a perfect
```