#include <bits/stdc++.h>
using namespace std;
const int N = 1e5 + 5;
int n, d, h, p[N], Cnt = 2;
int main() {
  cin >> n >> d >> h;
  if (d > 2 * h || d < h || n <= d || (h == d && d < 2 && n > 2)) {
    cout << -1 << endl;
    return 0;
  }
  for (int i = 2; i < h + 2; i++) {
    p[Cnt] = i - 1;
    Cnt++;
  }
  if (d > h) {
    p[Cnt] = 1;
    Cnt++;
    for (int i = h + 3; i < d + 2; i++) {
      p[i] = i - 1;
      Cnt++;
    }
  }
  for (int i = Cnt; i <= n; i++) {
    p[Cnt] = (d > h) ? 1 : 2;
    Cnt++;
  }
  for (int i = 2; i <= n; i++) cout << i << " " << p[i] << " " << endl;
  return 0;
}
