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

vector<pair<int,int> >v;
int main() {
    int q,n;
    cin>>q;
    while(q--)
    {
        int x,y;
        cin>>n;
        int mix=1000000,maax=-1000000,miy=1000000,maay=-1000000;
        v.clear();
        for(int i=0;i<n;i++)
        {
            cin>>x>>y;
            v.push_back(make_pair(x,y));
            mix=min(x,mix);
            maax=max(x,maax);
            miy=min(y,miy);
            maay=max(y,maay);
        }
        int coun=0;
        for(int i=0;i<n;i++)
        {
            if(v[i].first==mix||v[i].first==maax||v[i].second==miy||v[i].second==maay)
                coun++;
        }
        if(coun==n)cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}