#include <cmath>
#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 q;
    cin>>q;
    while(q--)
        {
        int n;
        cin>>n;
        vector<pair<int,int> >v,v1;
        for(int i=0;i<n;i++)
            {
            int x,y;
            cin>>x>>y;
            v.push_back(make_pair(x,y));
            v1.push_back(make_pair(y,x));
        }
        
        sort(v.begin(),v.end());
        int xmin=v[0].first;
        int xmax=v[n-1].first;
        
        sort(v1.begin(),v1.end());
        int ymin=v1[0].first;
        int ymax=v1[n-1].first;
        
        int flag=0;
        for(int i=0;i<n;i++)
            {
            int x=v[i].first;
            int y=v[i].second;
            if((x==xmin||x==xmax)||y==ymin||y==ymax)
                {
                continue;
            }
            else
                {
                flag=1;
                break;
            }
        }
        if(flag==0)cout<<"YES"<<endl;
        else cout<<"NO"<<endl;
    }
    return 0;
}