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