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.
The single line contains two integers *n* and *m* (3 ≤ *m* ≤ 100, *m* ≤ *n* ≤ 2*m*).
n,m=map(int,raw_input().split())
if m==3 and n>4:print-1
else:
 for i in range(m):print i,i*i
 for i in range(n-m):print i*i+10001,i