import java.util.*;
public class Hash {

	public static void main(String[] args) {
		Scanner in = new Scanner(System.in);
		int Q = in.nextInt();
		
		for(int q= 0; q<Q; q++)
		{
			int n = in.nextInt();
			int arr[] = new int[n];
			int array[] = new int[n];
			
			int minX = Integer.MAX_VALUE;
			int minY = Integer.MAX_VALUE;
			
			int maxX = Integer.MIN_VALUE;
			int maxY = Integer.MIN_VALUE;
			for(int i = 0; i<n; i++)
			{
				arr[i] = in.nextInt();
				if(arr[i] < minX)
				{
					minX = arr[i];
				}
				
				if(arr[i] > maxX)
				{
					maxX = arr[i];
				}
				
     			array[i] = in.nextInt();
     			if(array[i] < minY)
				{
					minY = array[i];
				}
				
				if(array[i] > maxY)
				{
					maxY = array[i];
				}
			}
			
			int count = 0;
			for(int i = 0; i<n; i++)
			{
				if((arr[i] == minX || arr[i] == maxX) && (array[i] <= maxY && array[i] >= minY))
				{
					count++;
				}	
				
				else if((array[i] == minY || array[i] == maxY) && (arr[i] <= maxX && arr[i] >= minX))
				{
					count++;
				}
			}
			
			if(count == n)
				System.out.println("YES");
			else
				System.out.println("NO");
			
		}
		in.close();

	}

}