import Control.Monad
import Control.Arrow

data Ans = YES | NO deriving Show

ans _ [] = YES
ans lim@((a,b),(u,v)) ((x@(y,z)):xs) 
  | y == a || y == u || z == b || z == v = ans lim xs
  | otherwise                            = NO

sol::[(Int,Int)] -> Ans
sol xs = ans ((u1,v1),(u2,v2)) xs
  where
  (us,vs) = unzip xs
  f       = minimum &&& maximum
  (u1,u2) = f us
  (v1,v2) = f vs

fun [a,b] = (a,b)
work = readLn >>= flip replicateM (fmap (fun.map read.words) getLine) >>= print.sol
main = readLn >>= flip replicateM_ work