#include <cstdio>

using namespace std;

int main()
{
    FILE *fin=fopen ("tije.in","r");
    FILE *fout=fopen ("tije.out","w");
    int n,x,i,j;
    fscanf (fin,"%d",&n);
    for (x=1;x<n;x++){ /// ai x-1 stive deja facute
        /// solve pt x;
        for (i=1;i<=n-1;i++)
            fprintf (fout,"%d %d\n",x,n+1);
        for (i=1;i<=x;i++)
            fprintf (fout,"%d %d\n",x+1,x);
        for (i=x+2;i<=n;i++){ /// transfer prefixul x-1..1 pe stiva x+1 si move ec in x
            for (j=1;j<=x-1;j++)
                fprintf (fout,"%d %d\n",i,x+1);
            fprintf (fout,"%d %d\n",i,x);
            for (j=1;j<=x-1;j++)
                fprintf (fout,"%d %d\n",x+1,i);
        }
        for (i=x+2;i<=n;i++)
            fprintf (fout,"%d %d\n",n+1,i); /// pui cate un x pe fiecare
        /// cum faci sa modifici tija x+1
        fprintf (fout,"%d %d\n",n+1,x+1); /// muti x ul
        for (i=1;i<=x-1;i++)
            fprintf (fout,"%d %d\n",x,x+1);
        for (i=1;i<=x-1;i++)
            fprintf (fout,"%d %d\n",n+1,x);
        for (i=1;i<=x-1;i++)
            fprintf (fout,"%d %d\n",x+1,n+1);
        for (i=1;i<=x-1;i++)
            fprintf (fout,"%d %d\n",x,x+1);
        for (i=1;i<=x-1;i++)
            fprintf (fout,"%d %d\n",n+1,x);
        //for (i=1;i<=x-1;i++)
          //  fprintf (fout,"%d %d\n",x+1,n+1);

    }
    return 0;
}