#include <iostream>
using namespace std;

int main() {
    freopen("tije.in", "r", stdin);
    freopen("tije.out", "w", stdout);
    
    int n;
    cin >> n;
    
    for (int i = 1; i < n; ++i) {
        int cnt = n - i;
        for (int j = 0; j < cnt; ++j) {
            cout << 1 << " " << n + 1 << "\n";
        }
        for (int j = 2; j <= n + 1; ++j) {
            for (int k = 0; k < cnt; ++k) {
                cout << j << " " << j - 1 << "\n";
            }
        }
    }
    
    return 0;
}