import java.io.*;
import java.util.*;
import java.text.*;
import java.math.*;
import java.util.regex.*;

public class Solution {

    public static int getmax(int[] a, int n) {
        int M = Integer.MIN_VALUE;
        for (int i=0; i<n; i++) {
            if (a[i] > M) {
                M = a[i];
            }
        }
        return M;
    }
    public static int getmin(int[] a, int n) {
        int m = Integer.MAX_VALUE;
        for (int i=0; i<n; i++) {
            if (a[i] < m) {
                m = a[i];
            }
        }
        return m;
    }
    public static void main(String[] args) {
        int[] xs = new int[10];
        int[] ys = new int[10];
        Scanner sc = new Scanner(System.in);
        int q = sc.nextInt();
        for (int d=0; d<q; d++) {
            boolean answer = true;
            int n = sc.nextInt();
            for (int j=0; j<n; j++) {
                xs[j] = sc.nextInt();
                ys[j] = sc.nextInt();
            }
            int ax = getmin(xs,n);
            int ay = getmin(ys,n);
            int bx = getmax(xs,n);
            int by = getmax(ys,n);
            
            // test if every point lies on one of these sides
            for (int i=0; i<n; i++) {
                int x = xs[i];
                int y = ys[i];
                if (x != ax && x != bx && y != ay && y != by) {
                    answer = false;
                }
            }
            if (answer) {
            System.out.println("YES");
            } else {System.out.println("NO");}
        }
        // end test case loop
    }
}