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 input = new Scanner(System.in);
        int q = input.nextInt();
        for (int i = 0; i < q; i++) {
            boolean isYes = true;
            int n = input.nextInt();
            int x1, x2, y1, y2;
            x1 = input.nextInt();
            y1 = input.nextInt();
            x2 = input.nextInt();
            y2 = input.nextInt();
            for (int j = 2; j < n; j++) {
                int x = input.nextInt();
                if (x != x1 && x != x2) {
                    isYes = false;
                    break;
                }
                int y = input.nextInt();
                if (y != y1 && y != y2) {
                    isYes = false;
                    break;
                }
            }
            if (!isYes) {
                System.out.println("YES");
            } else {
                System.out.println("NO");
            }
            
        }
        
    }
}