#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, n;
    cin>>q;
    while(q--)
    {
        cin>>n;
        int i=0, maxx=-10001, maxy=-10001, minx=10001, miny=10001;
        vector<pair<int, int>>p(n);
        while(i<n)
        {
            int x, y;
            cin>>x>>y;
            p[i]=make_pair(x, y);
            if(x>maxx)
                maxx=x;
            if(x<minx)
                minx=x;
            if(y>maxy)
                maxy=y;
            if(y<miny)
                miny=y;
            i++;
        }
        for(i=0; i<n; i++)
        {
            if(p[i].first<maxx&&p[i].first>minx&&p[i].second>miny&&p[i].second<maxy)
                break;
        }
        if(i==n)
            cout<<"YES\n";
        else
            cout<<"NO\n";
    }
    return 0;
}