Problem: 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 0
3 0
0 3
1 1


Input

6 3


Output

-1


Input

6 6


Output

10 0
-10 0
10 1
9 1
9 -1
0 -2


Input

7 4


Output

176166 6377
709276 539564
654734 174109
910147 434207
790497 366519
606663 21061
859328 886001

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
template <class T>
void chmax(T& a, const T& b) {
  a = max(a, b);
}
template <class T>
void chmin(T& a, const T& b) {
  a = min(a, b);
}
template <class T>
T round_up(T a, T b) {
  return (a + b - 1) / b;
}
template <class T>
void uniq(T& c) {
  sort(c.begin(), c.end());
  c.erase(unique(c.begin(), c.end()), c.end());
}
template <class T>
string to_s(const T& a) {
  ostringstream os;
  os << a;
  return os.str();
}
template <class T>
T to_T(const string& s) {
  istringstream is(s);
  T res;
  is >> res;
  return res;
}
template <class T, class U>
ostream& operator<<(ostream& os, pair<T, U>& p) {
  os << "( " << p.first << ", " << p.second << " )";
  return os;
}
template <class T>
void print(T a, int n, const string& deli = " ", int br = 1) {
  for (int i = 0; i < n; ++i) {
    cout << a[i];
    if (i + 1 != n) cout << deli;
  }
  while (br--) cout << endl;
}
template <class T>
void print(const T& c, const string& deli = " ", int br = 1) {
  for (__typeof__((c).begin()) it = (c).begin(); it != (c).end(); ++it) {
    cout << *it;
    if (++it != c.end()) cout << deli;
    --it;
  }
  while (br--) cout << endl;
}
template <class T>
void print2d(T a, int w, int h, int width = -1, int br = 1) {
  for (int i = 0; i < h; ++i) {
    for (int j = 0; j < w; ++j) {
      if (width != -1) cout.width(width);
      cout << a[i][j] << ' ';
    }
    cout << endl;
  }
  while (br--) cout << endl;
}
template <class T>
void input(T& a, int n) {
  for (int i = 0; i < n; ++i) cin >> a[i];
}
template <class T>
void input(T* a, int n) {
  for (int i = 0; i < n; ++i) cin >> a[i];
}
void fix_pre(int n) {
  cout.setf(ios::fixed, ios::floatfield);
  cout.precision(10);
}
void fast_io() {
  cin.tie(0);
  ios::sync_with_stdio(false);
}
bool in_rect(int x, int y, int w, int h) {
  return 0 <= x && x < w && 0 <= y && y < h;
}
const int dx[] = {0, 1, 0, -1};
const int dy[] = {1, 0, -1, 0};
const double PI = acos(-1.0);
int main() {
  int n, m;
  cin >> n >> m;
  if (m == 3) {
    int x[] = {0, 0, 1000, 55};
    int y[] = {0, 1000, 0, 58};
    if (n < 5) {
      for (int i = 0; i < (int)(n); ++i) printf("%d %d\n", x[i], y[i]);
    } else
      puts("-1");
  } else {
    vector<int> x, y;
    for (int i = 0; i < (int)(m); ++i) x.push_back(i), y.push_back(i * i);
    for (int i = 0; i < (int)(n - m); ++i)
      x.push_back(((long long)(1e6)) - i), y.push_back(-i * i);
    for (int i = 0; i < (int)(n); ++i) printf("%d %d\n", x[i], y[i]);
  }
}