#include <bits/stdc++.h>
using namespace std;
struct Timer {
  Timer() { beg = clock(); }
  ~Timer() {}
  clock_t beg;
};
int main() {
  ios_base::sync_with_stdio(false);
  int n, d, h;
  cin >> n >> d >> h;
  if (d < h) {
    cout << -1 << endl;
    return 0;
  }
  if (d == 1 && h == 1) {
    if (n == 2) {
      cout << 1 << " " << 2 << endl;
    } else {
      cout << -1 << endl;
    }
    return 0;
  }
  if (2 * h < d) {
    cout << -1 << endl;
    return 0;
  }
  if (n < d + 1) {
    cout << -1 << endl;
    return 0;
  }
  for (int i = 0; i < h; ++i) {
    cout << i + 1 << " " << i + 2 << endl;
  }
  if (d - h > 0) {
    cout << 1 << " " << h + 2 << endl;
  }
  for (int i = 0; i < d - h - 1; ++i) {
    cout << i + h + 2 << " " << i + h + 3 << endl;
  }
  for (int i = 0; i < n - d - 1; ++i) {
    cout << h << " " << i + d + 2 << endl;
  }
  return 0;
}
