#include <bits/stdc++.h>
using namespace std;
vector<int> months = {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
const int MAX = 1e5 + 55;
const int inf = 1e9 + 77;
const int MOD = 1e9 + 7;
const double PI = acos(-1.0);
const double eps = 1e-7;
int main() {
  int n;
  scanf("%d", &n);
  if (n >= 6) {
    int m = 5;
    int cnt = 3;
    for (int i = 2; i <= 4; ++i) printf("1 %d\n", i);
    int k = n - 4;
    while (k--) {
      printf("2 %d\n", m);
      ++m;
    }
  } else {
    printf("-1\n");
  }
  for (int i = 2; i <= n; ++i) printf("1 %d\n", i);
  return 0;
}
