import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static void main(String[] args) {
        /* Enter your code here. Read input from STDIN. Print output to STDOUT. Your class should be named Solution. */
        Scanner sc = new Scanner(System.in);
        int q = sc.nextInt();       
        for(int h = 0; h < q; h++){
            int n = sc.nextInt();
            int[] x = new int[n];
            int[] y = new int[n];
            for(int i = 0; i < n; i++){
                x[i] = sc.nextInt();
                y[i] = sc.nextInt();
            }
            int[] xSort = x;
            Arrays.sort(xSort);
            int[] ySort = y;
            Arrays.sort(ySort);        
            String edges = "YES";
            for(int k = 0; k < n; k++){
                if(x[k] > xSort[0] && x[k] < xSort[n - 1] && y[k] > ySort[0] && y[k] < ySort[n - 1]){
                    edges = "NO";
                }
            }
            System.out.println(edges);             
        }
    }
}