/*
TASK:mate
LANG:C
*/
#include <stdio.h>
int main ()
{
    int n,i,j;
    scanf ("%d",&n);
    printf ("%d\n",n);
    for (i=1;i<=n;i+=2)
        if (i+1>n) printf ("%d-%d ",i,1);
        else printf ("%d-%d ",i,i+1);
    printf ("\n");
    for (i=2;i<n;i++)
        {
            for (j=1;j<=n;j++)
                if (j+i>n) printf ("%d-%d ",j,i-(n-j));
                else printf ("%d-%d ",j,j+i);
            printf ("\n");
        }
    for (i=2;i<=n;i+=2)
        if (i+1>n) printf ("%d-%d ",i,1);
        else printf ("%d-%d ",i,i+1);
    printf ("\n");
    return 0;
}
