#include <bits/stdc++.h>
using namespace std;
int main() {
  int i, j, k, l, n, d, h;
  scanf("%d %d %d", &n, &d, &h);
  if (n == 2) {
    printf("1 2\n");
    return 0;
  }
  double a = ceil((double)d / 2);
  if (h < (int)a) {
    printf("-1\n");
    return 0;
  }
  if (h < 1 || d < 2 || h > d || h > n - 1 || d > n - 1) {
    printf("-1\n");
    return 0;
  }
  j = 1;
  for (k = 1; k <= h; k++, j++) printf("%d %d\n", j, j + 1);
  j++;
  int w = h - d;
  if (w < 0) {
    while (j <= n) {
      w = abs(w);
      int b = 0;
      printf("1 %d\n", j);
      j++;
      for (k = 1; k < w && j < n; k++, j++) {
        if (k == 1) j--;
        printf("%d %d\n", j, j + 1);
        b = 1;
      }
      if (b == 1) j++;
    }
  } else if (w == 0) {
    while (j <= n) {
      printf("2 %d\n", j);
      int b = 0;
      j++;
      for (k = 1; k < w && j < n; k++, j++) {
        if (k == 1) j--;
        printf("%d %d\n", j, j + 1);
        b = 1;
      }
      if (b == 1) j++;
    }
  }
  return 0;
}
