#include <bits/stdc++.h>
#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 n,q,i,j,p,mx,my,m1x,m1y;
    pair<int,int> k;
    cin>>q;
    while(q--){
        cin>>n;
        vector<pair<int ,int> > v;
        cin>>i>>j;v.push_back(make_pair(i,j));
        n--;mx=m1x=i;
        my=m1y=j;
        while(n--){
            cin>>i>>j;
            if(i>m1x)m1x=i;
            if(i<mx)mx=i;
            if(j>m1y)m1y=j; 
            if(j<my)my=j;
            v.push_back(make_pair(i,j));
        }
       for(i=0;i<v.size();++i){
           k=v[i];p=0;
           if(k.first==mx||k.first==m1x){
               if(k.second>=my&&k.second<=m1y)p=1;
               else {
                   p=0;
               }
           }
           else if(k.second==my||k.second==m1y){
               if(k.first>=mx&&k.first<=m1x)p=1;
               else{
                   p=0;
               }
           }
           else p=0;
           if(p==0)break;
       }
        if(p==0)cout<<"NO\n";
        else cout<<"YES\n";
        v.clear();
    }
    return 0;
}