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

public class Solution {
    static int[][] arr = new int[11][2];
    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 t = sc.nextInt();
        for(int k=0;k<t;k++){
            int n = sc.nextInt();
            if(n<=2){
                System.out.println("YES");
                for(int i=0;i<n;i++){
                    sc.nextInt();
                    sc.nextInt();
                }
                continue;
            }
            int xmin=Integer.MAX_VALUE,xmax=Integer.MIN_VALUE,ymin=Integer.MAX_VALUE,ymax=Integer.MIN_VALUE;
            for(int i=0;i<n;i++){
                int p=sc.nextInt();
                int q = sc.nextInt();
                arr[i][0]=p;
                arr[i][1]=q;
                xmin=Math.min(xmin,p);
                xmax=Math.max(xmax,p);
                ymin=Math.min(ymin,q);
                ymax=Math.max(ymax,q);
            }
            boolean tr=false;
            loop:
            for(int i=0;i<n;i++){
                if((arr[i][0]!=xmax && arr[i][0]!=xmin) && (arr[i][1]!=ymin && arr[i][1]!=ymax)){
                    System.out.println("NO");
                    tr=true;
                    break loop;
                }
            }
            if(tr) continue;
            System.out.println("YES");
        }
    }
}