using System;
using System.Collections.Generic;
using System.IO;
class Solution {
    static void Main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution */
        var queries = Convert.ToInt32(Console.ReadLine());
        
        for( int i = 0; i < queries; i++)
        {
            var numPoints = Convert.ToInt32(Console.ReadLine());
            
            var maxValue = 0;
            var minValue = 0;
            
            var output = "YES";
            
            for (int j = 0; j < numPoints; j++)
            {
                var positions = Console.ReadLine().Split(' ');
                
                var x = Convert.ToInt32(positions[0]);
                var y = Convert.ToInt32(positions[1]);
                                
                maxValue = x > maxValue ? x : maxValue;
                minValue = x < minValue ? x : minValue;
                maxValue = y > maxValue ? y : maxValue;
                minValue = y < minValue ? y : minValue;
                
                if ((x != maxValue && x!= minValue) || (y != maxValue && y != minValue)) 
                {
                    output = "NO";
                    break;
                }
            }
            
            Console.WriteLine(output);
        }
    }
}