#include <bits/stdc++.h>
using namespace std;
long long n, d, h;
int main() {
  std::ios::sync_with_stdio(false);
  cin >> n >> d >> h;
  if (n == 2) {
    cout << "1 2";
    return 0;
  }
  if (d > h * 2 || d == 1) {
    cout << "-1";
    return 0;
  }
  long long val = h;
  long long inceput = 1;
  long long nr = n - h;
  while (val > 0) {
    cout << inceput << " " << inceput + 1 << endl;
    n--;
    inceput++;
    val--;
  }
  if (d > h) {
    val = d - h - 1;
    cout << "1 " << inceput + 1 << endl;
    n--;
    inceput++;
    while (val > 0) {
      cout << inceput << " " << inceput + 1 << endl;
      n--;
      inceput++;
      val--;
    }
  }
  if (d != h) {
    val = 1;
  } else {
    val = 2;
  }
  nr = inceput;
  while (n > 1) {
    nr++;
    cout << val << " " << nr << endl;
    n--;
  }
  return 0;
}
