1 1 1
1000000000
2 1
 20 2 15
12698951 55128070 116962690 156763505 188535242 194018601 269939893 428710623 442819431 483000923 516768937 552903993 633087286 656092270 671535141 714291344 717660646 846508634 879748146 937368929
2 7
1 2
2 4
1 19
1 12
1 5
2 18
2 11
1 16
2 1
2 3
2 19
1 17
2 9
2 6
 6 3 10
62417580 78150524 410053501 582708235 630200761 760672946
2 2
1 5
1 2
1 4
2 4
2 1
2 1
1 6
2 5
2 6

NO
 NO
NO
NO
NO
NO
NO
YES
NO
NO
 NO
YES
NO
NO
YES
YES

#include <bits/stdc++.h>
using namespace std;
long long int power(long long int a, long long int b) {
  long long int res = 1;
  while (b > 0) {
    if (b % 2) res *= a;
    a *= a;
    b >>= 1;
  }
  return res;
}
int main() {
  ios_base::sync_with_stdio(false);
  cin.tie(0);
  long long int n, d, h;
  cin >> n >> d >> h;
  std::vector<pair<long long int, long long int> > v;
  long double D = d;
  D /= 2;
  if (ceil(D) > h || h > d)
    cout << "-1"
         << "\n";
  else {
    long long int a, b;
    a = h;
    b = d - a;
    long long int i;
    long long int root = 1;
    for (i = 2; i <= a + 1; i++) v.push_back(make_pair(i - 1, i));
    long long int j = b;
    while (b--) {
      v.push_back(make_pair(root, i));
      root = i;
      i++;
    }
    root = 1;
    long long int c = 0;
    b++;
    for (; i <= n; i++) {
      c = (c + 1) % b;
      if (c == 0) root = 1;
      v.push_back(make_pair(root, i));
      root = i;
    }
    for (long long int f = 0; f < v.size(); f++)
      cout << v[f].first << " " << v[f].second << "\n";
  }
  return 0;
}
