#include <fstream>
using namespace std;
ifstream f("tije.in");
ofstream g("tije.out");
int n,i,j,t;
int main()
{
    f>>n;
    for(i=n-1;i>=1;--i)
    {
        for(j=n;j>=1;--j)
            for(t=1;t<=i;++t ) g<<j<<" "<<j+1<<'\n';
        for (j=1;j<=i;++j) g<<n+1<<" 1"<<'\n';
    }

    return 0;
}