#include<bits/stdc++.h>
using namespace std ;
#define maxn 200009
#define ll long long
#define pb push_back
#define fi first
#define se second
#define left id<<1
#define right id<<1|1
#define re exit(0);
#define _lower(x) lower_bound(v.begin(),v.end(),x)-v.begin()+1
const int mod = 1e9+7 ;
const int INF = 1e9 ;
typedef vector<int> vi ;
typedef pair<int,int> pii ;
typedef vector<pii> vii ;
template < typename T > void chkmin ( T &a , T b ) { if ( a > b ) a = b ; }
template < typename T > void chkmax ( T &a , T b ) { if ( a < b ) a = b ; }
void add ( int &a , int b )
{
a += b ;
if ( a >= mod ) a -= mod ;
if ( a < 0 ) a += mod ;
}
void rf ()
{
freopen ("bai1.inp","r",stdin) ;
}
int _pow ( int a , int n )
{
if ( n == 0 ) return 1 ;
int res = _pow (a,n/2) ;
if ( n % 2 ) return 1ll*res*res%mod*a%mod ;
else return 1ll*res*res%mod ;
}
int n ;
int Query ( int i , int j , int k ) ;
void Bridge ( int i , int j ) ;
void Solve ( int N ) ;
//void Answer ( int x , int y ) ;
void Answer ( int x , int y )
{
if ( x > y ) swap (x,y) ;
Bridge (x,y) ;
}
void Calc ( vi v )
{
if ( v.size () == 1 ) return ;
random_shuffle (v.begin(),v.end()) ;
map <int,vi> m ;
m [v[0]] . pb (v[0]) , m [v[1]] . pb (v[1]) ;
vi path ;
for ( int i = 2 ; i < v.size () ; i ++ )
{
int x = Query (v[0],v[1],v[i]) ;
if ( !m.count(x) ) path . pb (x) ;
m [x] . pb (v[i]) ;
}
sort (path.begin(),path.end(),[&](int x , int y )
{
return (Query (v[0],x,y) == x ) ;
});
int last = v[0] ;
for ( auto x : path ) Answer (last,x) , last = x ;
Answer (last,v[1]) ;
for ( auto it : m ) Calc (it.second) ;
}
void Solve ( int N )
{
n = N ;
vi all (n) ;
for ( int i = 0 ; i < n ; i ++ ) all [i] = i ;
Calc (all) ;
}
