#include<stdio.h>
int main ()
{
    int i,j,k,n;
    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(k=1;k<=i;k++)
                    printf("%d %d\n",j,j+1);
            for(j=1;j<=i;j++)
                printf("%d 1\n",n+1);
        }
    return 0;
}