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

public class Solution {

    public static void main(String[] args) {
        
		Scanner scanner = new Scanner(System.in);

		int q = scanner.nextInt();

		for (int a = 0; a < q; a++) {

			int n = scanner.nextInt();
			List<Integer> xList = new ArrayList<Integer>();
			List<Integer> yList = new ArrayList<Integer>();

			for (int i = 0; i < n; i++) {
				xList.add(scanner.nextInt());
				yList.add(scanner.nextInt());
			}

			int xMax = Collections.max(xList);
			int yMax = Collections.max(yList);

			int xMin = Collections.min(xList);
			int yMin = Collections.min(yList);

			String doesFall = "YES";
			for (int i = 0; i < n; i++) {
				if ((xList.get(i) < xMax && yList.get(i) < yMax) && (xList.get(i) > xMin && yList.get(i) > yMin)) {
					doesFall = "NO";
					break;
				}
			}
			System.out.println(doesFall);
		}

		scanner.close();

	
    }
}