# Enter your code here. Read input from STDIN. Print output to STDOUT
q = int(raw_input())
for p in range(0,q):
	n = int(raw_input())
	x_array = []
	y_array = []
	min_index_x, min_x = [0 , 10000]
	min_index_y, min_y = [0 , 10000]
	for q in range(0, n):
		xtemp , ytemp = raw_input().split()
		xtemp, ytemp = int(xtemp), int(ytemp)
		x_array.append(xtemp)
		y_array.append(ytemp)
		if min_x > xtemp:
			min_x = xtemp
			min_index_x = q
		if min_y > ytemp:
			min_y = ytemp
			min_index_y = q
	net_min_index = 0
	if (x_array[min_index_x] ** 2 + y_array[min_index_x] ** 2) > (x_array[min_index_y] **2 + y_array[min_index_y] ** 2):
		net_min_index = min_index_x
	else:
		net_min_index = min_index_y
	far_x = x_array[net_min_index]
	index_far_x = net_min_index
	for q in range(0,n):
		if y_array[net_min_index] == y_array[q] and x_array[q] > x_array[net_min_index]:
			index_far_x = q
			far_x = x_array[q]
	far_y = y_array[net_min_index]
	index_far_y = net_min_index
	for q in range(0,n):
		if x_array[net_min_index] == x_array[q] and y_array[q] > y_array[net_min_index]:
			index_far_y = q
			far_y = y_array[q]
	X1 = x_array[net_min_index]
	Y1 = y_array[net_min_index]
	X2 = far_x
	Y2 = far_y
	printthing = "YES"
	for q in range(0,n):
		if x_array[q] == X1 or x_array[q] == X2 or y_array[q] == Y1 or y_array[q] == Y2:
			printthing = "YES"
		else:
			printthing = "NO"
			break
	print printthing