#include <bits/stdc++.h>
using namespace std;

#define REP(i, a, b) for (int i = a; i <= b; i++)
#define FOR(i, n) for (int i = 0; i < n; i++)
#define foreach(it, ar) for ( typeof(ar.begin()) it = ar.begin(); it != ar.end(); it++ )
#define fill(ar, val) memset(ar, val, sizeof(ar))
#define PI 3.1415926535897932385
#define uint64 unsigned long long
#define Int long long
#define int64 long long
#define all(ar) ar.begin(), ar.end()
#define pb push_back
#define ff first
#define ss second
#define bit(n) (1<<(n))
#define Last(i) ( (i) & (-i) )
#define sq(x) ((x) * (x))
#define INF INT_MAX
#define mp make_pair
#define MAXN 101



int main ( )
 {
    int t ;
    cin >>  t ;
    while(  t  -- )
     {
          int n ;
          cin >> n  ;
          vector< pair<int,int> >   vx(0) ;
          vector< pair<int,int> >   vy(0) ;

          FOR( p , n )
           {
              int x , y  ;
              cin >>  x >> y  ;
              vx.pb( mp( x, y ) ) ;
              vy.pb( mp (y ,x ) )  ;
           }


              sort(  vx.begin() ,  vx.end() ) ;
              sort(  vy.begin( ) , vy.end() ) ;

              int lx = vx[0].ff ;
              int rx = vx[n-1].ff ;
              int ay = vy[n-1].ff ;
              int by = vy[0].ff ;
              int i = 0 ;
              for( i = 0 ; i <  n ; i ++ )
                {
                   int x = vx[i].ff ;
                   int y = vx[i].ss ;
                   if(  ( y == ay ||  y == by )  && ( x>= lx && x <= rx) )
                             continue ;

                   if(  ( x == lx ||  x == rx )  && ( y >= by && y <= ay ) )
                             continue ;

                  break ;

                }

             if(  i == n )cout<< "YES"<<endl;
             else cout<<"NO"<<endl;


     }

 }