#include <bits/stdc++.h>
using namespace std;
const int maxn = 1e5 + 5;
vector<int> g[maxn];
int n, d, h;
int vis[maxn];
long long p[maxn];
void solve() {
  for (int i = 1; i <= n; i++) g[i].clear();
  memset(vis, 0, sizeof(vis));
  int mn = h / 2;
  if (h % 2) mn++;
  int mx = h;
  if (d < mn || d > mx) {
    puts("-1");
    return;
  }
  int lb = h - d;
  int ub = d;
  int l = 2;
  int cc = 0, root = 1;
  if (lb) {
    for (;;) {
      g[root].push_back(l);
      vis[root] = 1;
      vis[l] = 1;
      root = l;
      l++;
      cc++;
      if (cc == lb) break;
    }
  }
  root = 1;
  cc = 0;
  if (ub) {
    for (;;) {
      g[root].push_back(l);
      vis[root] = 1;
      root = l;
      vis[l] = 1;
      l++;
      cc++;
      if (cc == ub) break;
    }
  }
  int cnt = 0;
  for (int i = 1; i <= n; i++) {
    if (vis[i]) cnt++;
  }
  if (cnt < n) {
    int v = 0;
    if (lb)
      v = 1;
    else {
      for (int i = 0; i < g[1].size(); i++) {
        int u = g[1][i];
        if (g[u].size() >= 1) {
          v = u;
          break;
        }
      }
    }
    if (v == 0) {
      puts("-1");
      return;
    }
    for (int i = l; i <= n; i++) {
      g[v].push_back(i);
      vis[i] = 1;
    }
  }
  for (int i = 1; i <= n; i++) {
    if (!vis[i]) {
      puts("-1");
      return;
    }
  }
  for (int i = 1; i <= n; i++) {
    for (int j = 0; j < g[i].size(); j++) {
      printf("%d %d\n", i, g[i][j]);
    }
  }
}
int main() {
  while (scanf("%d %d %d", &n, &h, &d) != EOF) {
    solve();
  }
  return 0;
}
