#include<iostream>
#include<string>

using namespace std;

#define FOR(i,a,b)for(i=(a);i<=(b);++i)
#define FORN(i,a,b)for(i=(a);i>=(b);--i)

int N;

int main()
{
    int layer,pile,hm;
    
    freopen("tije.in","r",stdin);
    freopen("tije.out","w",stdout);
    
    scanf("%d",&N);
    
    FOR(layer,1,N)
    {
      int to_move=N-layer;
      
      FORN(pile,N,1)
        FOR(hm,1,to_move)
          printf("%d %d\n",pile,pile+1);
       
      FOR(hm,1,to_move)
        printf("%d %d\n",N+1,1);    
    }  
    
    return 0;
}