#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int t;
    cin>>t;
    while(t--){
        int n;
        cin>>n;
        vector<pair<int,int> > a(n);
        int minx=10001,miny=10001,maxx=-10001,maxy=-10001,flag=1;
        a.clear();
        for(int i=0;i<n;i++){
            int x,y;
            cin>>x>>y;
            a.push_back(make_pair(x,y));
            if(x<minx) minx=x;
            if(y<miny) miny=y;
            if(x>maxx) maxx=x;
            if(y>maxy) maxy=y;
        }
        for(vector<pair<int,int> > ::iterator i=a.begin();i!=a.end();i++){
            //cout<<i->first<<" "<<i->second<<endl;
            if(( i->first!=minx && i->first!=maxx) && (i->second!=miny && i->second!=maxy)){ flag=0; break; }
        }
      if(flag)  cout<<"YES\n";
        else  cout<<"NO\n"; 
    }
    return 0;
}