# Enter your code here. Read input from STDIN. Print output to STDOUT

t = gets.strip.to_i

t.times do
    n = gets.strip.to_i
    
    xx = []
    yy = []
    
    _x = {}
    _y = {}
    
    n.times do
        x, y = gets.strip.split(" ").map(&:to_i)
        xx << x
        yy << y
        _x[x] ||= []
        _y[y] ||= []
        _x[x] << y
        _y[y] << x
    end
    
    minx, maxx = xx.minmax
    miny, maxy = yy.minmax
    
    yes = true
  
    xx.zip(yy).each do |x, y|
        next if x == minx || x == maxx
        next if y == miny || y == maxy
        yes = false
    end
    
    if yes
        puts "YES"
    else
        puts "NO"
    end
end