#include <iostream>

int main() {
  freopen("tije.in", "r", stdin);
  freopen("tije.out", "w", stdout);
  
  int N;
  std::cin >> N;
  for(int i = N - 1; i >= 1; i--) {
    for (int j = N; j >= 1; j--) {
      for (int k = 1; k <= i; k++) {
        std::cout << j << ' ' << j + 1 << '\n';
      }
    }
    for (int j = 1; j <= i; j++) {
      std::cout << N + 1 << ' ' << 1 << '\n';
    }
  }
  return 0;
}