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

#define INF 1000000
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(n);
        
        for(int i=0; i<n; i++){cin>>arr[i].first>>arr[i].second;}
 
        int mx_x=-INF, mx_y=-INF, mn_x=INF, mn_y=INF;
        for(int i=0; i<n; i++){
            
            if(arr[i].first>mx_x)mx_x=arr[i].first;
            if(arr[i].first<mn_x)mn_x=arr[i].first;
            
            if(arr[i].second>mx_y)mx_y=arr[i].second;
            if(arr[i].second<mn_y)mn_y=arr[i].second;
        }
        //if(mx_x==mn_x || mx_y==mn_y){cout<<"NO"<<'\n'; continue;}
        bool b=0;
        for(int i=0; i<n; i++){
            
            if(arr[i].first!=mn_x && arr[i].first!=mx_x && arr[i].second!=mn_y && arr[i].second!=mx_y){b=1;break;}
        }
        if(b)cout<<"NO"<<'\n';
        else cout<<"YES"<<'\n';
    }
    return 0;
}