#include <bits/stdc++.h>
using namespace std;
const int N = 1e5;
long long int n;
int main() {
  long long int n;
  cin >> n;
  if (n == 2 || n == 3 || n == 4 || n == 5) {
    cout << -1 << '\n';
  } else {
    if (n % 2 == 0) {
      for (int i = 2; i <= n / 2 + 1; i++) {
        cout << 1 << " " << i << '\n';
      }
      for (int i = n / 2 + 2; i <= n; i++) {
        cout << 2 << " " << i << '\n';
      }
    }
    if (n % 2 == 1) {
      for (int i = 2; i <= n / 2 + 2; i++) {
        cout << 1 << " " << i << '\n';
      }
      for (int i = n / 2 + 3; i <= n; i++) {
        cout << 2 << " " << i << '\n';
      }
    }
  }
  for (int i = 2; i <= n; i++) {
    cout << 1 << " " << i << '\n';
  }
  return 0;
}
