#include <stdio.h>

int N,i,j,k,CNT;

int main()
{
	freopen("tije.in","r",stdin);
	freopen("tije.out","w",stdout);

	scanf("%d ",&N);

	for (i=1,CNT=0;i<N;i++,CNT++)
	{
		for (j=1;j<=N;j++) printf("%d %d\n",i,N+1);

		for (j=i+1;j<=N;j++)
			{
			for (k=1;k<=CNT;k++)
				printf("%d %d\n",j,j-1);
			printf("%d %d\n",j,i);
			}

		printf("%d %d\n",N+1,i);
		for (j=i+1;j<=N;j++)
			printf("%d %d\n",N+1,j);

		for (j=1;j<=CNT;j++)
			printf("%d %d\n",N+1,N);
	}

	return 0;
}