#include <cstdio>

int N;

int main()
{
    freopen("tije.in","rt",stdin);
    freopen("tije.out","wt",stdout);

    scanf("%d",&N);

    for(int i = N - 1; i; --i)
    {
        for(int j = N; j; --j)
            for(int k = i; k; --k)
                printf("%d %d\n",j, j+1);
        for(int j = i; j; --j)
            printf("%d 1\n",N+1);
    }
}