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