#include <iostream>
#include <fstream>

using namespace std;

int N;

int main()
{
    ifstream f("tije.in");
    ofstream g("tije.out");

    f >> N;

    for ( int i = 1; i < N; ++i )
    {
        for ( int j = i; j <= N; ++j ) /// mut pe aux
                g << i << " " << N + 1 << "\n";

        for ( int j = i + 1; j <= N; ++j )
                g << j << " " << i << "\n";

        for ( int j = N; j >= i; j-- )
                g << N + 1 << " " << j << "\n";
    }

    return 0;
}