#include <bits/stdc++.h>
using namespace std;
int main() {
  ios_base::sync_with_stdio(0);
  cin.tie(0);
  cout.tie(0);
  int n, d, h;
  cin >> n >> d >> h;
  if (d < h || n < (d + 1) || d > 2 * h)
    cout << "-1";
  else {
    if (d == 1 && n >= 3) {
      cout << -1;
      return 0;
    }
    for (int i = 2; i < h + 2; ++i) {
      cout << i - 1 << " " << i << '\n';
    }
    if (d == h) {
      for (int i = h + 2; i <= n; ++i) {
        cout << "2 " << i << '\n';
      }
    } else {
      for (int i = h + 2; i <= d + 1; ++i) {
        if (i == h + 2)
          cout << "1 " << i << '\n';
        else
          cout << i - 1 << " " << i << '\n';
      }
      for (int i = d + 2; i <= n; ++i) {
        cout << "1 " << i << '\n';
      }
    }
  }
}
