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