#include <bits/stdc++.h>

using namespace std;

int main() {
  cin.tie(0)->sync_with_stdio(0);
  int n; cin >> n;
  if (n > 1 && n < 6) return cout << "NO", 0;
  cout << "YES\n";
  if (n == 6) {
    cout << "6\n1 2\n2 3\n1 3\n3 4\n2 5\n5 6\n";
    return 0;
  }
  cout << n - 1 << '\n';
  if (n == 1) return 0;
  cout << "1 2\n1 3\n3 4\n1 5\n";
  for (int i = 6; i <= n; ++i) cout << i << ' ' << i - 1 << '\n';
}