#include<stdio.h>
int n,i,j,k;
int main()
{freopen("tije.in", "r",stdin);
freopen("tije.out", "w",stdout);
scanf("%d",&n);
for(i=n-1;i>=1;i--)
  {for(j=n;j>=1;j--)
     for(k=1;k<=i;k++)
	   printf("%d %d\n",j,j+1);
  for(k=1;k<=i;k++)
    printf("%d 1\n",n+1);}
return 0;}