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 in = new Scanner(System.in);
        int q = in.nextInt();
        for (int i=0;i<q;i++) {
            int n = in.nextInt();
            List<Integer> x = new ArrayList<Integer>();
            List<Integer> y = new ArrayList<Integer>();

            for (int j=0;j<n;j++) {
                x.add(in.nextInt());
                y.add(in.nextInt());

            }
            int xmax = Collections.max(x);
            int xmin = Collections.min(x);
            int ymax = Collections.max(y);
            int ymin = Collections.min(y);
            
            String outer = "YES";
            for (int j=0;j<n;j++) {
                if ((x.get(j)==xmax) || (x.get(j)==xmin) || (y.get(j)==ymin)||(y.get(j)==ymax) )  {
                } else {
                        outer="NO";
                        break;
                }
            } 
            System.out.println(outer);
        }
    }
}