#include <stdio.h>

int N,i,j,k;

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

	scanf("%d ",&N);

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

	return 0;
}