#include<stdio.h>
FILE*f=fopen("tije.in","r");
FILE*g=fopen("tije.out","w");
long i,j,n,k,x;
long a[100][100];
int main(void)
{
fscanf(f,"%ld",&n);
for(i=1;i<=n;i++)
	{
	a[0][i]=n;
	for(j=1;j<=n;j++)
		a[j][i]=i;
	}
n=n;
for(i=n-1;i>=1;i--)
{
	for(j=n;j>=1;j--)
		{
		for(k=1;k<=i;k++)
		 {
		 x=a[a[0][j]][j];
		 a[a[0][j]][j]=0;
		 a[0][j]--;
		 a[0][j+1]++;
		 a[a[0][j+1]][j+1]=x;
		 fprintf(g,"%ld %ld\n",j,j+1);
		 }
		}
	for(k=1;k<=i;k++)
	{
	x=a[a[0][n+1]][n+1];
	a[a[0][n+1]][n+1]=0;
	a[0][n+1]--;
	a[0][1]++;
	a[a[0][1]][1]=x;
	fprintf(g,"%ld 1\n",n+1);
  }
}
return 0;
}