#include<fstream>

using namespace std;

const char iname[]="tije.in";
const char oname[]="tije.out";

ifstream f(iname);
ofstream g(oname);

int n,i,j,k;

int main()
{
    f>>n;
    for(i=1;i<n;++i)
    {
        for(j=n;j;--j)
            for(k=i;k;--k)
                g<<j<<" "<<j+1<<"\n";
        for(k=i;k;--k)
            g<<n+1<<" 1\n";
    }

    f.close();
    g.close();

    return 0;
}