#include <cmath>
#include <cstdio>
#include <vector>
#include <iostream>
#include <bits/stdc++.h>
using namespace std;


int main() {
    int q;
    cin>>q;
    while(q--)
        {
        int n,i;
        cin>>n;
        int xmax=INT_MIN;
        int xmin=INT_MAX;
        int ymax=INT_MIN;
        int ymin=INT_MAX;
        int x[n],y[n];
        for(i=0;i<n;i++)
            {
            cin>>x[i]>>y[i];
            if(x[i]>xmax)xmax=x[i];
            if(x[i]<xmin)xmin=x[i];
            if(y[i]>ymax)ymax=y[i];
            if(y[i]<ymin)ymin=y[i];
        }
        for(i=0;i<n;i++)
            {
            if(x[i]==xmax||x[i]==xmin||y[i]==ymax||y[i]==ymin)
                {}
            else break;
        }
        if(i==n)cout<<"YES\n";
        else cout<<"NO\n";
    }
    return 0;
}