#include <bits/stdc++.h>
using namespace std;
int n, d, h;
bool f = true;
vector<pair<int, int> > e;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(NULL);
  cin >> n >> d >> h;
  if (d == h && h == 1) {
    if (n >= 3) {
      cout << -1;
      return 0;
    }
  }
  if (d - h > h || n < d + 1) f = false;
  for (int i = 0; i < h; i++) e.push_back(make_pair(i + 1, i + 2));
  if (d - h > 0) {
    e.push_back(make_pair(1, h + 2));
    for (int i = 0; i < d - h - 1; i++)
      e.push_back(make_pair(i + 1 + h + 1, i + 2 + h + 1));
    for (int i = 0; i < n - d - 1; i++)
      e.push_back(make_pair(1, i + 1 + d + 1));
  } else {
    for (int i = 0; i < n - h - 1; i++) e.push_back(make_pair(2, h + i + 2));
  }
  if (f) {
    for (auto e_ : e) cout << e_.first << ' ' << e_.second << endl;
  } else {
    cout << -1;
  }
  return 0;
}
