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

public class Solution {
    private static int min,max;
    
    private static void findMinMax(ArrayList<Integer> al){
            min = al.get(0);
            max = al.get(0);
            for(Integer i: al) {
                if(i < min) min = i;
                if(i > max) max = i;
            }
    }

    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();
            ArrayList<Integer> X = new ArrayList<Integer>();
            ArrayList<Integer> Y = new ArrayList<Integer>();
            for(int j = 0;j<n;j++){
                X.add(in.nextInt());
                Y.add(in.nextInt());
            }
            
            findMinMax(X);
            int x_min = min;
            int x_max = max;
            
            findMinMax(Y);
            int y_min = min;
            int y_max = max;

            int cnt = 0;
            
            for(int j=0;j<n;j++){
                if(X.get(j) == x_min || X.get(j)== x_max || Y.get(j) == y_min || Y.get(j) == y_max){
                    ++cnt;
                }
            }

            
            if(cnt == n){
                System.out.println("YES");
            }else{
                System.out.println("NO");
            }
        }
    }
}