#include <bits/stdc++.h>
using namespace std;
int main() {
  ios::sync_with_stdio(false);
  cin.tie(0);
  cout.precision(15);
  cout << fixed;
  srand(time(0));
  int n, d, h;
  cin >> n >> d >> h;
  int a = d, b = h;
  if (2 * h < d || n > 2 && d == 1) {
    cout << "-1";
    return 0;
  }
  d -= h;
  int c = 2;
  while (d--) {
    cout << c - 1 << " " << c << "\n";
    c++;
  }
  int x = c;
  while (h--) {
    if (c == x) {
      cout << 1 << " " << c << "\n";
    } else {
      cout << c - 1 << " " << c << "\n";
    }
    c++;
  }
  while (c <= n) {
    if (a == b) {
      cout << (c++) << " 2\n";
    } else {
      cout << (c++) << " 1\n";
    }
  }
  return 0;
}
