using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
class Solution
{
    class Points
    {
        public int x;
        public int y;
        public Points(int x,int y)
        {
            this.x = x; this.y = y;
        }
    }


    static void Main(String[] args)
    {
        int cases = Convert.ToInt32(Console.ReadLine());
        while (cases > 0)
        {
            cases--;
            int n = Convert.ToInt32(Console.ReadLine());
            Points[] pts = new Points[n];
            List<Points> online = new List<Points>();
            for (int i = 0; i < n; i++)
            {
                string[] c_temp = Console.ReadLine().Split(' ');
                pts[i] = new Points(Int32.Parse(c_temp[0]), Int32.Parse(c_temp[1]));

            }
            int xmax = pts.Select(x => x.x).Max();
            int ymax = pts.Select(x => x.y).Max();
            int xmin = pts.Select(x => x.x).Min();
            int ymin = pts.Select(x => x.y).Min();
            
            foreach (var item in pts)
            {
                if (item.x == xmin || item.x == xmax || item.y == ymin || item.y == ymax)
                    online.Add(item);
            }
            if(pts.Length==online.Count())
                Console.WriteLine("YES");
            else
                Console.WriteLine("NO");
           
        }
    }
}