The coordinattes of $n$ points are given on a plane. Print them in increasing order of their abscissa. In the case of a tie, sort the points in decreasing order of ordinate.

Input

Each line contains the pair of numbers $x,y(0≤x,y≤10_{9})$ — the coordinates of one point.

Output

Print the points in the required order. Print the coordinates of each point on a separate line.