#include <fstream>

using namespace std;

int n, i, j, k;

int main()
{
    ifstream cin("tije.in");
    ofstream cout("tije.out");
    cin >> n;
    for(i = 1 ; i < n ; ++ i)
    {
        for(j = n ; j ; -- j)
            for(k = 1; k <= i ; ++ k)
                cout << j << " " << j+1 << "\n";
        for(k = 1 ; k <= i ; ++ k)
            cout << n+1 << " " << 1 << "\n";
    }

    return 0;
}