from math import atan2, degrees, pi

def get_angle(x1, y1, x2, y2):
    dx = x2 - x1
    dy = y2 - y1
    rads = atan2(-dy,dx)
    rads %= 2*pi
    degs = degrees(rads)
    return degs

def get_dist(x1, y1, x2, y2):
    minx = min(x1, x2)
    maxx = max(x1, x2)
    miny = min(y1, y2)
    maxy = max(y1, y2)
    return abs(maxx-minx) + abs(maxy-miny)

q = int(input())
for i in range(q):
    n = int(input())
    X = []
    Y = []
    dist = {}
    for j in range(n):
        x,y = list(map(int,input().split()))
        X.append(x)
        Y.append(y)
    minx = min(X)
    maxx = max(X)
    miny = min(Y)
    maxy = max(Y)
    rect = True
    for j in range(n):
        if (X[j]==minx or X[j]==maxx or Y[j]==miny or Y[j]==maxy):
            rect = True
        else:
            rect = False
            break

    if (rect):
        print("YES")
    else:
        print("NO")