#include <bits/stdc++.h>
using namespace std;
template <typename T>
T expo(T e, T n) {
  T x = 1, p = e;
  while (n) {
    if (n & 1) x = x * p;
    p = p * p;
    n >>= 1;
  }
  return x;
}
template <typename T>
T power(T e, T n, T m) {
  T x = 1, p = e;
  while (n) {
    if (n & 1) x = (x * p) % m;
    p = (p * p) % m;
    n >>= 1;
  }
  return x;
}
template <typename T>
T InverseEuler(T a, T m) {
  return (a == 1 ? 1 : power(a, m - 2, m));
}
template <typename T>
T gcd(T a, T b) {
  while (a %= b ^= a ^= b ^= a)
    ;
  return b;
}
template <typename T>
T lcm(T a, T b) {
  return (a * (b / gcd(a, b)));
}
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...);
}
long long n, d, h;
int32_t main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  cout.tie(0);
  cin >> n >> d >> h;
  if (d >= n || d > 2 * h || d < h) {
    cout << "-1\n";
    return 0;
  }
  if (d == 1 && n > 2) {
    cout << "-1\n";
    return 0;
  }
  long long node = 2, e;
  for (__typeof(h) i = 1; i <= h; ++i) {
    cout << node - 1 << " " << node << endl;
    node++;
  }
  e = node;
  if (d != h) {
    cout << 1 << " " << node << endl;
    node++;
    for (__typeof(d - h - 1) i = 1; i <= d - h - 1; ++i) {
      cout << node - 1 << " " << node << endl;
      node++;
    }
    while (node <= n) {
      cout << 1 << " " << node << endl;
      node++;
    }
  } else {
    while (node <= n) {
      cout << 2 << " " << node << endl;
      node++;
    }
  }
  return 0;
}
