#include <bits/stdc++.h>
#pragma comment(linker, "/STACK:64000000")
using namespace std;
int n, d, h;
vector<vector<int> > g;
int main() {
  cin >> n >> d >> h;
  g.resize(n);
  if (d > h * 2) {
    cout << -1;
    return 0;
  }
  int f = 1;
  if (h == 1) {
    if (d == 1) {
      if (n > 2) {
        cout << -1;
        return 0;
      }
    }
    while (f < n) {
      cout << 1 << " " << f + 1 << endl;
      f++;
    }
  } else {
    for (int i = 0; i < h; ++i) {
      cout << f << " " << f + 1 << endl;
      f++;
    }
    for (int i = 0; i < d - h; ++i) {
      if (i == 0) {
        cout << 1 << " " << f + 1 << endl;
      } else
        cout << f << " " << f + 1 << endl;
      f++;
    }
    while (f < n) {
      cout << 2 << " " << f + 1 << endl;
      f++;
    }
  }
}
