#include <bits/stdc++.h>
using namespace std;
using namespace std::chrono;
template <typename T>
void printarr(T *A, int n) {
  for (int i = 0; i < n; i++) {
    cout << A[i] << " ";
  }
  cout << "\n";
}
template <typename T>
void arrinit(T *A, int n, T data) {
  for (int i = 0; i < n; i++) {
    A[i] = data;
  }
}
template <typename T>
void takeinput(T *A, int n) {
  for (int i = 0; i < n; i++) {
    cin >> A[i];
  }
}
template <typename T>
void printcont(T A) {
  for (auto a : A) {
    cout << a << " ";
  }
  cout << "\n";
}
template <typename T>
T binpowmod(T a, T b, T p) {
  if (b == 0) return 1;
  if (b == 1) return a;
  if (b % 2 == 0)
    return ((binpowmod(a, b / 2, p) % p) * (binpowmod(a, b / 2, p) % p)) % p;
  return ((a % p) * (binpowmod(a, b - 1, p) % p)) % p;
}
template <typename T>
T gcd(T a, T b) {
  if (a == 0) return b;
  if (b == 0) return a;
  if (a == b) return a;
  if (a > b) return gcd(b, a % b);
  return gcd(b % a, a);
}
class dsu {
 public:
  vector<int> p;
  vector<int> r;
  dsu(int n, vector<int> c) {
    r.assign(n, 1);
    for (int i = 0; i < n; i++) p.push_back(c[i] - 1);
  }
  int get(int a) { return p[a] = (p[a] == a ? a : get(p[a])); }
  void merge(int a, int b) {
    a = get(a);
    b = get(b);
    if (r[a] == r[b]) r[a]++;
    if (r[a] < r[b]) {
      p[a] = b;
    } else
      p[b] = p[a];
  }
};
const long long mod = 1e9 + 7;
long long bpm(long long x, long long a) {
  if (a == 0) return 1 % mod;
  if (a == 1) return x % mod;
  if (a % 2 == 0)
    return ((bpm(x, a / 2) % mod) * (bpm(x, a / 2) % mod)) % mod;
  else
    return ((x % mod) * (bpm(x, a - 1) % mod)) % mod;
}
void solve() {
  int n, d, h;
  cin >> n >> d >> h;
  if (h < (d + 1) / 2) {
    cout << -1 << "\n";
    return;
  }
  vector<pair<int, int>> e;
  for (int i = 1; i <= h; i++) {
    e.push_back({i, i + 1});
  }
  if (d >= h + 1) {
    e.push_back({1, h + 2});
    int maxs = h + 3;
    for (int i = 1; i < d - h; i++) {
      e.push_back({h + i + 1, h + i + 2});
      maxs = h + i + 3;
    }
    while (e.size() < n - 1) {
      e.push_back({1, maxs});
      maxs++;
    }
  } else {
    if (d == 1) {
      if (n != 2) {
        cout << -1 << "\n";
        return;
      }
    }
    int x = h + 2;
    while (e.size() < n - 1) {
      e.push_back({2, x});
      x++;
    }
  }
  for (auto c : e) {
    cout << c.first << " " << c.second << "\n";
  }
}
int main() {
  auto start = high_resolution_clock::now();
  {
    ios_base::sync_with_stdio(false);
    cin.tie(0);
    cout.tie(0);
  }
  long long t = 1;
  for (long long i = 0; i < t; i++) {
    solve();
  }
  auto stop = high_resolution_clock::now();
  auto duration = duration_cast<milliseconds>(stop - start);
  return 0;
}
