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

bool f(pair<int, int> a, pair<int, int> b){
    return a.second>b.second;
}

int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */   
    int q;
    cin>>q;
    for(int qq=0;qq<q;qq++){
        int n, a,b;
        cin>>n;
        vector<pair<int, int> > si;
        for(int i=0;i<n;i++){
            cin>>a>>b;
            si.push_back(make_pair(a, b));
        }
        if(n==1 || n==2){
            cout<<"YES"<<endl;
            continue;
        }
        bool ok=true;
        sort(si.begin(), si.end());
        int xl=si[0].first, xr=si[si.size()-1].first;
        sort(si.begin(), si.end(), f);
        int yu=si[si.size()-1].second, yd=si[0].second;
        for(int i=0;i<n;i++){
            if((si[i].first!=xl && si[i].first!=xr)&&(si[i].second!=yu && si[i].second!=yd)){
                cout<<"NO"<<endl;
                ok=false;
                break;
            }
        }
        if(ok)
            cout<<"YES"<<endl;
        else
            continue;
    }
    return 0;
}