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


int main() {
    int q;
    cin>>q;
    while(q--)
        {
        int n;
        cin>>n;
        int minx=100000,maxx=-100000,miny=100000,maxy=-100000;
        int x[1000],y[1000];
        bool flag = true;
        for(int i=0;i<n;i++)
            {
            
            cin>>x[i]>>y[i];
            if(minx>x[i])
                minx = x[i];
            if(maxx<x[i])
                maxx = x[i];
            miny = min(miny,y[i]);
            maxy = max(maxy,y[i]);
        }
        for(int i=0;i<n;i++)
            {
            if(x[i] == minx || x[i] == maxx)
                continue;
            if(y[i] == miny || y[i] ==maxy)
                continue;
            else
                {
                flag = false;break;
            }
        }
        if(flag == true)
            cout<<"YES"<<endl;
        else
            cout<<"NO"<<endl;
        
    }
    return 0;
}