import java.io.*;
import java.util.*;

public class Solution {

    public String query(List<int[]> points, int pointNum){
        
        Collections.sort(points, (a, b) ->(a[0] - b[0]));
        int minX = points.get(0)[0];
        int maxX = points.get(pointNum - 1)[0];
        
        Collections.sort(points, (a, b) -> (a[1] - b[1]));
        int minY = points.get(0)[1];
        int maxY = points.get(pointNum - 1)[1];
        
        for (int[] point : points){
            boolean ok = false;
            if (point[0] == minX || point[0] == maxX){
                ok = true;
            } 
            if (point[1] == minY || point[1] == maxY){
                ok = true;
            }
            if (!ok){
                return "NO";
            }
        }
        return "YES";
    
    }
    
    public static void main(String[] args) {
        Solution soln = new Solution();
        Scanner in = new Scanner(System.in);
        int queryNum = Integer.parseInt(in.nextLine());
        for (int i = 0 ; i < queryNum; i++){
            int pointNum = Integer.parseInt(in.nextLine());
            List<int[]> points = new ArrayList<>();
            for (int j = 0 ; j < pointNum; j++){
                String[] input = in.nextLine().split("\\s+");
                points.add(new int[]{Integer.parseInt(input[0]), Integer.parseInt(input[1])});
            }
            System.out.println(soln.query(points, pointNum));
        }
    }
}