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


int main() {
    
    int q;
    cin>>q;
    while(q--){
        int minx=INT_MAX,miny=INT_MAX,maxx=INT_MIN,maxy=INT_MIN;
        int n;
        cin>>n;
        int a[n],b[n];
        for(int i=0;i<n;i++){
            cin>>a[i]>>b[i];
        }
        for(int i=0;i<n;i++){
            if(minx>a[i]){minx=a[i];}
            
            if(miny>b[i]){miny=b[i];}
            
            if(maxx<a[i]){maxx=a[i];}
            
            if(maxy<b[i]){maxy=b[i];}
        }
        int c=0;
        for(int i=0;i<n;i++){
            if(a[i]!=minx&&a[i]!=maxx&&b[i]!=miny&&b[i]!=maxy){
                c++;
                break;
            }
        }
        if(c==0){
            cout<<"YES"<<endl;
        }
        else{
            cout<<"NO"<<endl;
        }
    }
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    return 0;
}