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