B. Set of Points
time limit per test
2 seconds
memory limit per test
256 megabytes
input
standard input
output
standard output

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 ≤ 2m).

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 108 in their absolute value.

Examples
Input
4 3
Output
0 03 00 31 1
Input
6 3
Output
-1
Input
6 6
Output
10 0-10 010 19 19 -10 -2
Input
7 4
Output
176166 6377709276 539564654734 174109910147 434207790497 366519606663 21061859328 886001