#include <bits/stdc++.h>
using namespace std;
void setup() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cout.precision(15);
}
template <typename Arg1>
void __f(const char* name, Arg1&& arg1) {
  cerr << name << " : " << arg1 << std::endl;
}
template <typename Arg1, typename... Args>
void __f(const char* names, Arg1&& arg1, Args&&... args) {
  const char* comma = strchr(names + 1, ',');
  cerr.write(names, comma - names) << " : " << arg1 << " | ";
  __f(comma + 1, args...);
}
int main() {
  int n, d, h;
  cin >> n >> d >> h;
  if (h == 1 and d == 1 and n != 2) {
    cout << "-1\n";
    return 0;
  }
  if (d > 2 * h) {
    cout << "-1\n";
    return 0;
  }
  int prev = 1, cur = 2;
  for (int i = 1; i <= h; i++) {
    cout << prev << " " << cur << '\n';
    prev = cur;
    cur++;
  }
  if (h == d) {
    prev = cur - 2;
    for (int i = 1; i <= n - 1 - d; i++) {
      cout << prev << " " << cur << '\n';
      cur++;
    }
    return 0;
  }
  prev = 1;
  for (int i = 1; i <= d - h; i++) {
    cout << prev << " " << cur << '\n';
    prev = cur;
    cur++;
  }
  for (int i = 1; i <= n - 1 - d; i++) {
    cout << 1 << " " << cur << '\n';
    cur++;
  }
  return 0;
}
