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



	return 0;
}