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, input().split())


if m == 3:
    if n >= 5:
        print(-1)
        exit(0)
    print(0, 0)
    print(2, 0)
    print(1, 1)
    if n >= 4:
        print(1, 2)
    exit(0)


for i in range(m):
    print(i, 10**7 + i**2)

for i in range(n - m):
    print(i, -10**7 - i**2)
