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