#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);  
    }  
}