#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;



int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q;
    cin>>q;
    while(q--){
        int n;cin>>n;
        vector<pair<int,int> > arr;
        int maxx=INT_MIN,maxy=INT_MIN,minx=INT_MAX,miny=INT_MAX;
        for(int i=0;i<n;i++){
            int a,b;cin>>a>>b;
               maxx=max(maxx,a);
               maxy=max(maxy,b);
               minx=min(minx,a);
               miny=min(miny,b);
            arr.push_back({a,b});
        }
        int goal=1;
        for(int i=0;i<n;i++){
            if(arr[i].first==maxx|| arr[i].first==minx || arr[i].second==maxy || arr[i].second==miny)
            continue;
            goal=0;
            cout<<"NO"<<endl;break;
            
        }
        if(goal)
        cout<<"YES"<<endl;
        
    }
    
    
    return 0;
}