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