#include<stdio.h>
FILE *f,*g;
long int nn,ii,x[10],n,i,j;
void solve(long int n);
int main()
{   f=fopen("tije.in","r");g=fopen("tije.out","w");
    fscanf(f,"%ld",&nn);
    for(n=nn;n>=3;n--)
    {   for(i=1;i<=n;i++)
	fprintf(g,"1 %ld\n",n+1);
	fprintf(g,"%ld 1\n",n);
	for(i=1;i<=n-1;i++)
	fprintf(g,"%ld 1\n",n+1);
	for(i=2;i<=n-1;i++)
	 { for(j=1;j<=n-i;j++)
	   fprintf(g,"%ld %ld\n",i,n+1);
	   fprintf(g,"%ld %ld\n",n,n+1);
	   for(j=1;j<=i;j++)
	   fprintf(g,"%ld %ld\n",i,n);
	   fprintf(g,"%ld %ld\n",n+1,i);
	   for(j=1;j<=i;j++)
	   fprintf(g,"%ld %ld\n",n,i);
	   for(j=1;j<=n-i-1;j++)
	   fprintf(g,"%ld %ld\n",n+1,i);
	 }
    }
    fprintf(g,"1 3\n");
    fprintf(g,"2 1\n");
    fprintf(g,"3 2\n");
    for(n=3;n<=nn;n++)
     for(j=1;j<=n-1;j++)
      fprintf(g,"%ld %ld\n",n+1,n);
    fcloseall();
    return 0;
}