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

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 t = in.nextInt();
        
        while(t-->0){
            
            int n = in.nextInt();
            int xmax = 0;
            int xmin = 0;
            int ymin = 0;
            int ymax = 0;
            int[] x = new int[n];
            int[] y = new int[n];
            for(int i=0;i<n;i++){
                x[i]  = in.nextInt();
                y[i]  = in.nextInt();
                
               
                if(x[i]>xmax){
                    xmax = x[i];
                }else if(x[i]<xmin){
                    xmin  = x[i];
                }
                 if(y[i]>ymax){
                    ymax = y[i];
                }else if(y[i]<ymin){
                    ymin  = y[i];
                }
            }
            // System.out.println(xmax+" "+xmin+" "+ymin+" "+ymax);
            int c=0;
            for(int i=0;i<n;i++){
                if(x[i]==xmin || x[i]==xmax || y[i]==ymin || y[i]==ymax){
                    c++;
                   
                }
            }
            
            if(c==n){
                System.out.println("YES");
            }else  System.out.println("NO");
            
        }
    }
}