#include<stdio.h>

int n;

int main ()
{
    int i,j,t;
    freopen("tije.in","r",stdin);
    freopen("tije.out","w",stdout);
    scanf("%d",&n);
    for(i=1;i<n;i++)
    {
        for(j=n;j>=1;j--)
            for(t=1;t<=i;t++)
                printf("%d %d\n",j,j+1);
        for(j=1;j<=i;j++)
            printf("%d 1\n",n+1);
    }
    return 0;
}