#include<stdio.h>

int i,j,n,l;

int main(){


FILE *f=fopen("tije.in","r");
fscanf(f,"%d",&n);
fclose(f);

FILE *g=fopen("tije.out","w");

   for(i=n-1;i>=1;i--){

     for(j=n;j>n-i;j--){
     fprintf(g,"%d %d\n",n,n+1);
     }

     for(l=n-1;l>=1;l--){
        for(j=n;j>n-i;j--)
        fprintf(g,"%d %d\n",l,l+1);
     }

      for(j=n;j>n-i;j--){
      fprintf(g,"%d %d\n",n+1,1);
      }

   }

fclose(g);

return 0;
}