Given a rectangle, along with an even number of points in its interior, find a way to split the points evenly into two halves with a single cut; that is, partition the points into two sets A and B of equal size such that there exists a straight line that divides the rectangle into two pieces of equal area corresponding to the two sets.  If a point lies exactly on the dividing line, it is counted in exactly one set of your choice.

Input format:

Input will consist of multiple test cases.  Each test case begins with a line with 3 space-separated integers N, W, and H, denoting the number of points, the width of the rectangle, and the height of the rectangle, respectively.  The rectangle's four corners are (0,0), (w,0), (0,h), and (w,h).  Following this line are N lines each with a pair of space-separated integers x_i and y_i denoting the coordinates of the ith point.

2 <= N <= 50000, 2 <= W <= 10000, 2 <= H <= 10000, N is even, W and H are not both even.
0 < x_i < W for all i, 0 < y_i < H for all i.  All points are distinct.

Input will be terminated with a case where N = W = H = 0, which should not be processed.

Output format:

For each test case, print out N/2 lines.  On each line, print two space-separated integers x_i and y_i, denoting the coordinates of the ith point in set A.

Sample input:

2 5 6
2 3
3 3
4 5 6
1 5
2 5
3 5
4 5
4 10 11
5 1
5 2
5 3
5 4
0 0 0

Sample output:

3 3
1 5
2 5
5 1
5 2