#include <bits/stdc++.h>
using namespace std;
const long long mod = 1000000007;
long long rowNum[] = {-1, 0, 0, 1};
long long colNum[] = {0, -1, 1, 0};
int main() {
  int n, d, h;
  cin >> n >> d >> h;
  if (d > n - 1 || d < h || d > 2 * h || (n > 2 && h < 2 && d == h)) {
    cout << "-1\n";
    return 0;
  }
  int prev = 0;
  for (long long i = 1; i < h + 1; i++) {
    cout << prev + 1 << ' ' << i + 1 << endl;
    prev = i;
  }
  if (d == h) {
    for (long long i = h + 1; i < n; i++) {
      cout << "2 " << i + 1 << endl;
    }
    return 0;
  }
  prev = 0;
  for (long long i = h + 1; i < d + 1; i++) {
    cout << prev + 1 << ' ' << i + 1 << endl;
    prev = i;
  }
  for (long long i = d + 1; i < n; i++) {
    cout << "1 " << i + 1 << endl;
  }
}
