#include <stdio.h>
long i,j,n,k;

int main()
{
 freopen("tije.in","r",stdin);
 freopen("tije.out","w",stdout);
 scanf("%ld",&n);
 for (i=n-1;i>=1;i--)
 {
  for (j=n;j>=1;j--)
   for (k=1;k<=i;k++)
    printf("%ld %ld",j,j+1);
  for (k=1;k<=i;k++)
   printf("%ld %ld",n+1,1);
 }
 fclose(stdin);
 fclose(stdout);
}