#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  int n, d, h;
  cin >> n >> d >> h;
  if (d > 2 * h || d >= n || (h == 1 && d == 1 && n != 2))
    cout << "-1" << '\n';
  else {
    int i = 1, j = 1, cnt = 0;
    while (cnt < h) {
      cout << i << " " << i + 1 << '\n';
      cnt++;
      i++;
    }
    if (d > h) {
      d = d - h;
      while (d--) {
        cout << j << " " << i + 1 << '\n';
        i++;
        j = i;
        cnt++;
      }
    }
    if (d == h) {
      while (cnt < n - 1) {
        cout << 2 << " " << i + 1 << '\n';
        i++;
        cnt++;
      }
    } else {
      while (cnt < n - 1) {
        cout << 1 << " " << i + 1 << '\n';
        i++;
        cnt++;
      }
    }
  }
  return 0;
}
