Given a triangle, find the circumcircle center of the given triangle. A circumcircle center of a triangle is a point whose distances to three point are the same. The coordinates of all points are integers. The coordinates of the circumcircle center must be integers too. It is possible that no such circumcircle center exists.
The input contains several test cases. In each test case, there are six integers representing the three coordinates of a triangle on a 2D plane. All the input integers are ranged from -1000 to 1000. You can assumed that no three coordinates will be collinear.
For each test case, print the coordinate of the circumcircle center. If the coordinates of the circumcirle center are not integers, print -1.