#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(nullptr);
  int n, d, h;
  cin >> n >> d >> h;
  if (h + h < d || n < d + 1 || (n > 2 && d == 1)) {
    cout << -1 << '\n';
    return 0;
  }
  int prev = 1;
  for (int i = 0; i < h; i++) {
    cout << prev << ' ' << prev + 1 << '\n';
    ++prev;
  }
  ++prev;
  int tc = 1;
  for (int i = 0; i < d - h; i++) {
    cout << prev << ' ' << tc << '\n';
    tc = prev;
    ++prev;
  }
  for (int i = 0; i < n - d - 1; i++) {
    cout << (1 + (d == h)) << ' ' << prev << '\n';
    ++prev;
  }
  return 0;
}
