#include <bits/stdc++.h>
using namespace std;
long long int choose(long long int n, long long int m) {
  long long int ans = 0;
  long long int num = 1;
  long long int den = 1;
  for (long long int i = 0; i < m; i++) {
    num *= (n - i);
    num = num / (i + 1);
  }
  return num;
}
bool isPrime(int n) {
  if (n <= 1) return false;
  if (n <= 3) return true;
  if (n % 2 == 0 || n % 3 == 0) return false;
  for (int i = 5; i * i <= n; i = i + 6) {
    if (n % i == 0 || n % (i + 2) == 0) return false;
  }
  return true;
}
long long int gcd(long long int a, long long int b) {
  if (a == 0) {
    return b;
  } else {
    return gcd(b % a, a);
  }
}
int main() {
  long long int i, j = 1, k, n, m, t, d, h, y;
  cin >> n >> d >> h;
  long long int newnode = 2, leftnodes = n;
  if (d > 2 * h) {
    cout << -1 << endl;
  } else {
    if (h == 1 && d == 1 && n != 2) {
      cout << -1 << endl;
    } else {
      cout << 1 << " " << newnode << endl;
      leftnodes -= 2;
      m = 1;
      while (m != h) {
        cout << newnode << " " << newnode + 1 << endl;
        newnode++;
        leftnodes--;
        m++;
      }
      newnode++;
      long long int leftdia = d - h;
      if (leftdia == 0) {
        y = 2;
        while (leftnodes != 0) {
          cout << 2 << " " << newnode << endl;
          newnode++;
          leftnodes--;
          y++;
        }
      } else {
        cout << 1 << " " << newnode << endl;
        leftdia--;
        leftnodes--;
        while (leftdia != 0) {
          cout << newnode << " " << newnode + 1 << endl;
          newnode++;
          leftnodes--;
          leftdia--;
        }
        while (leftnodes != 0) {
          cout << 1 << " " << newnode + 1 << endl;
          newnode++;
          leftnodes--;
        }
      }
    }
  }
  return 0;
}
