#include <stdio.h>
int main ()
{
	FILE *in  = fopen("tije.in","r");
	FILE *out = fopen("tije.out","w");
	
	int n,i,j,k;//,count=0;

	fscanf(in,"%d",&n);		
//	int v[105][105];
//	for (i=1; i<=n; i++)
//		for (j=0; j<=n; j++)
//			if (j==0)
//				v[i][j]=n;
//			else
//				v[i][j]=i;
	for (i=n; i>1; i--)
	{
		for (j=n-1; j>0; j--)//,count++)
		{
			fprintf(out,"%d %d\n",i,n+1);
//			v[n+1][++v[n+1][0]]=v[i][v[i][0]];			
//			v[i][v[i][0]--]=0;
		}
		for (j=n-i+1; j>0; j--)//,count++)
		{
			fprintf(out,"%d %d\n",i-1,i);
//			v[i][++v[i][0]]=v[i-1][v[i-1][0]];
//			v[i-1][v[i-1][0]--]=0;
		}
		for (j=i-2; j>0; j--)
		{
			for (k=n-i; k>0; k--)//,count++)
			{
				fprintf(out,"%d %d\n",j,j+1);
//				v[j+1][++v[j+1][0]]=v[j][v[j][0]];
//				v[j][v[j][0]--]=0;
			}
//			count++;
			fprintf(out,"%d %d\n",n+1,j+1);
//			v[j+1][++v[j+1][0]]=v[n+1][v[n+1][0]];
//			v[n+1][v[n+1][0]--]=0;
//			count++;
			fprintf(out,"%d %d\n",j,i);
//			v[i][++v[i][0]]=v[j][v[j][0]];
//			v[j][v[j][0]--]=0;
		}
		for (j=n-i+1; j>0; j--)//,count++)
		{
			fprintf(out,"%d %d\n",n+1,1);
//			v[1][++v[1][0]]=v[n+1][v[n+1][0]];
//			v[n+1][v[n+1][0]--]=0;
		}
	}
//	printf("au fost facuti %d pasi.",count);
	return 0;
}