# Enter your code here. Read input from STDIN. Print output to STDOUT
q = int(raw_input())
while q>0:
    n=int(raw_input())
    x=list()
    y=list()
    flag=False
    for i in range(n):
        n1,n2 = map(int, raw_input().split())
        x.append(n1)
        y.append(n2)
    for i in range(n):
        if (x[i]==min(x) and min(y)<=y[i]<=max(y)) or (y[i]==min(y) and min(x)<=x[i]<=max(x)) or (x[i]==max(x) and min(y)<=y[i]<=max(y)) or (y[i]==max(y) and min(x)<=x[i]<=max(x)):
            flag=True
        else:
            flag=False
    if(flag==True):
        print "YES"
    else:
        print "NO"
    q-=1