#include <bits/stdc++.h>
using namespace std;
#pragma GCC optimize("-O3")
using ld = long double;
const long long mod = 1000000007;
const long long inf = 1000000000000000000;
const long long rk = 256;
const ld PI = 3.141592653589793;
ostream& operator<<(ostream& os, pair<long long, long long> const& x) {
  os << x.first << "," << x.second;
  return os;
}
template <class T>
ostream& operator<<(ostream& os, vector<T> const& x) {
  os << "{ ";
  for (auto& y : x) os << y << " ";
  return os << "}";
}
template <class T>
ostream& operator<<(ostream& os, set<T> const& x) {
  os << "{ ";
  for (auto& y : x) os << y << " ";
  return os << "}";
}
template <class Ch, class Tr, class Container>
basic_ostream<Ch, Tr>& operator<<(basic_ostream<Ch, Tr>& os,
                                  Container const& x) {
  os << "{ ";
  for (auto& y : x) os << y << " ";
  return os << "}";
}
template <class X, class Y>
ostream& operator<<(ostream& os, pair<X, Y> const& p) {
  return os << "[ " << p.first << ", " << p.second << "]";
}
const int mx = 1e6 + 10;
int32_t main() {
  long long n, d, h;
  cin >> n >> d >> h;
  if (d > 2 * h || (h == d && d == 1 && n > 2))
    cout << "-1\n";
  else {
    for (int i = 1; i <= h; i++) cout << i << " " << i + 1 << '\n';
    int j = 1;
    for (int i = h + 2; i <= d + 1; i++) {
      cout << j << " " << i << '\n';
      j = i;
    }
    for (int i = d + 2; i <= n; i++) cout << h << " " << i << '\n';
  }
  return 0;
}
