#include <bits/stdc++.h>
using namespace std;
int dx[] = {0, 0, 1, -1, -1, -1, 1, 1};
int dy[] = {1, -1, 0, 0, -1, 1, 1, -1};
template <class T>
inline T gcd(T a, T b) {
  while (b) {
    a %= b;
    swap(a, b);
  }
  return a;
}
template <class T>
inline T bigmod(T p, T e, T m) {
  long long ret = 1;
  for (; e > 0; e >>= 1) {
    if (e & 1) ret = (ret * p) % m;
    p = (p * p) % m;
  }
  return (T)ret;
}
inline int nxt() {
  int aaa;
  scanf("%d", &aaa);
  return aaa;
}
vector<pair<int, int> > v;
int main() {
  long long a, b, c;
  cin >> a >> b >> c;
  if (b == 1 && c == 1 && a > 2) {
    puts("-1");
    return 0;
  }
  if (b > c * 2) {
    puts("-1");
    return 0;
  }
  if (b < c) {
    puts("-1");
    return 0;
  }
  int node = 1;
  int i = 1;
  for (i = 1; i <= c; i++) {
    v.push_back(pair<int, int>(i, i + 1));
    node++;
  }
  int temp = b - c + i;
  int check = 0;
  i++;
  for (; i <= temp; i++) {
    if (!check) {
      v.push_back(pair<int, int>(1, i));
      check = 1;
    } else
      v.push_back(pair<int, int>(i - 1, i));
    node++;
  }
  if (node > a) {
    puts("-1");
    return 0;
  }
  while (node != a) {
    if (c != b)
      v.push_back(pair<int, int>(1, i++));
    else
      v.push_back(pair<int, int>(2, i++));
    node++;
  }
  for (int i = 0; i < v.size(); i++)
    cout << v[i].first << " " << v[i].second << endl;
  return 0;
}
