#include <fstream>

using namespace std;
ifstream fin("tije.in");
ofstream fout("tije.out");

int main()
{
    int n,i,j,l;
    fin>>n;
    for(i=n-1; i>0; i--)
    {
        for(j=n; j>0; j--)
            for(l=1; l<=i; l++)
                fout<<j<<" "<<j+1<<'\n';
        for(j=1; j<=i; j++)
            fout<<n+1<<" "<<1<<'\n';
    }
    return 0;
}