#include <bits/stdc++.h>
#define endl '\n';
using namespace std;
typedef long long int LL;

vector<pair<int,int> >v;

bool cmp(pair<int,int> a, pair<int,int> b)
{
  if(a.first<b.first)return true;
  if(a.first>b.first)return false;
  return a.second>b.second;
}

int main()
{
  ios_base::sync_with_stdio(false);cin.tie(0);

  //freopen("input.in","r",stdin);
  
   int q;cin>>q;while(q--)
   {
   	  int n;
   	  cin>>n;
   	  v.clear();
   	  vector<int>a,b;
   	  for(int i=0;i<n;i++)
   	  {
   	  	int x,y;
   	  	cin>>x>>y;
   	  	v.push_back(make_pair(x,y));
   	  	a.push_back(x);
   	  	b.push_back(y);
   	  }
   	  sort(a.begin(),a.end());
   	  sort(b.begin(),b.end());
   	  bool fnf=true;
   	  for(int i=0;i<n;i++)
   	  {
        if(!( (v[i].first==a[0]|| v[i].first==a[n-1])||(v[i].second==b[0]|| v[i].second==b[n-1])))
        {
           fnf=false;break;
        }
   	  }
   	  string res= (fnf) ? "YES" : "NO";
   	  cout<<res<<endl;
   }
          
  
  return 0;
}