#include <bits/stdc++.h>
using namespace std;
int main() {
  long long int n, h, d;
  cin >> n >> d >> h;
  if (d > 2 * h || (d == h && h == 1 && n != 2)) {
    cout << -1 << endl;
    return 0;
  } else {
    long long int cur = 1;
    long long int dep = 0;
    long long int f = 0;
    for (long long int i = 2; i <= n; i++) {
      if (f == 0) {
        if (dep + 1 <= h)
          cout << cur << " " << i << endl, cur = i, dep++;
        else
          f = 1, i--;
      } else if (d - h > 0) {
        if (dep + 1 <= d - h)
          cout << cur << " " << i << endl, cur = i, dep++;
        else
          cout << 1 << " " << i << endl, cur = i, dep = 1;
      } else
        cout << 2 << " " << i << endl;
    }
  }
  return 0;
}
