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