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*).
def f(x):
    return int(x * x + 1e7)
    
def g(x):
    return -f(x)
    
n, m = map(int, input().split())

if(m == 3):
    if(n == 3):
        print('0 0')
        print('1 0')
        print('0 1')
    elif(n == 4):
        print('0 0')
        print('1 2')
        print('3 2')
        print('4 0')
    else:
        print(-1)
else:
    for i in range(m):
        print(i, f(i))
    for i in range(n - m):
        print(i, g(i))