#include<cstdio>
using namespace std;
int n,i,j,k;
int main()
{
    freopen("tije.in","r",stdin);
    freopen("tij.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;
}