#include<cstdio>

using namespace std;

int n,i,j,k;

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