#include <bits/stdc++.h>
using namespace std;
const int M = 2e5;
int infty = 1e9;
int p[M], t[M];
int main() {
  int n, d, h;
  cin >> n >> d >> h;
  if (2 * h < d || (n > 2 && d == 1)) {
    cout << -1 << '\n';
  } else {
    int h1 = h, h2 = d - h, cur = 2;
    for (int i = 0; i < h; i++) {
      cout << cur - 1 << ' ' << cur << '\n';
      cur++;
    }
    if (d == h) {
      for (int i = cur; i <= n; i++) {
        cout << 2 << ' ' << i << '\n';
      }
    } else {
      if (h2 > 0) {
        cout << "1 " << cur << '\n';
        cur++;
      }
      for (int i = 1; i < h2; i++) {
        cout << cur - 1 << ' ' << cur << '\n';
        cur++;
      }
      for (int i = cur; i <= n; i++) {
        cout << 1 << ' ' << i << '\n';
      }
    }
  }
  return 0;
}
