#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(NULL);
  int n, d, h;
  cin >> n >> d >> h;
  if (n == 2) {
    cout << 1 << " " << 2 << endl;
    return 0;
  }
  if (h < (d + 1) / 2 || (d == h && d == 1 && n > 2)) {
    cout << -1;
    return 0;
  }
  vector<int> t(d + 1);
  t[h] = 1;
  int k = 2;
  for (int i = 0; i < t.size(); i++)
    if (i != h) t[i] = k++;
  for (int i = 0; i < t.size() - 1; i++)
    cout << t[i] << " " << t[i + 1] << endl;
  while (k <= n) cout << t[t.size() / 2] << " " << k++ << endl;
  return 0;
}
