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