Convexity of a set of points on the plane is the size of the largest subset of points that form a convex polygon. Your task is to build a set of $*n*$ points with the convexity of exactly $*m*$. Your set of points should not contain three points that lie on a straight line.

Input

The single line contains two integers $*n*$ and $*m*$ ($3 ≤ *m* ≤ 100, *m* ≤ *n* ≤ 2*m*$).

Output

If there is no solution, print "-1". Otherwise, print $*n*$ pairs of integers — the coordinates of points of any set with the convexity of $*m*$. The coordinates shouldn't exceed $10^{8}$ in their absolute value.