#include <cstdio>
using namespace std;
int n,i,j,t;
int main()
{
    freopen("tije.in","r",stdin);
    freopen("tije.out","w",stdout);
    scanf("%d",&n);
    for(i=n-1;i>=1;--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;
}