#include <bits/stdc++.h>
using namespace std;
int main() {
  int n, d, h;
  scanf("%d%d%d", &n, &d, &h);
  if (n != 2 && h == 1 && d == 1) {
    printf("-1\n");
    return 0;
  }
  if (d > 2 * h || d < h) {
    printf("-1\n");
    return 0;
  }
  int curr = 2;
  if (d == h) {
    for (int i = 0; i < h; i++) {
      printf("%d %d\n", curr - 1, curr);
      curr++;
    }
    for (int i = 0; i < n - h - 1; i++) {
      printf("%d %d\n", 2, curr);
      curr++;
    }
    return 0;
  }
  for (int i = 1; i <= h; i++) {
    printf("%d %d\n", curr - 1, curr);
    curr++;
  }
  printf("%d %d\n", 1, curr);
  curr++;
  for (int i = 1; i < d - h; i++) {
    printf("%d %d\n", curr - 1, curr);
    curr++;
  }
  for (int i = 0; i < n - d - 1; i++) {
    printf("%d %d\n", 1, curr);
    curr++;
  }
}
