#include <bits/stdc++.h>
using namespace std;
long long input() {
  long long x = 0, f = 0;
  char ch = getchar();
  while (ch < '0' || ch > '9') f |= ch == '-', ch = getchar();
  while (ch >= '0' && ch <= '9') x = x * 10 + ch - '0', ch = getchar();
  return f ? -x : x;
}
long long n, d, h;
long long cnt = 1;
int main() {
  n = input();
  d = input();
  h = input();
  if (d == 1 && h == 1 && n > 2) {
    printf("-1\n");
    return 0;
  }
  if (d > 2 * h) {
    printf("-1\n");
    return 0;
  } else {
    for (int i = 1; i <= h; i++) {
      printf("%d %d\n", i, i + 1);
      cnt++;
    }
    if (cnt <= n && d != h) {
      cnt++, printf("%d %d\n", 1, cnt);
      for (int i = cnt; i <= d; i++) {
        printf("%d %d\n", i, i + 1);
        cnt++;
      }
    }
    cnt++;
    if (d == h) {
      for (int i = cnt; i <= n; i++) {
        printf("2 %d\n", i);
      }
    } else
      for (int i = cnt; i <= n; i++) {
        printf("1 %d\n", i);
      }
  }
}
